scubalab reviews state-of-the-art breathers - Atomic Aquatics

00 S C U B A D I V I N G JULY 2007 JULY 2007 S C U B A D I V I N G . C O M 71

12SCUBALAB REVIEWS

STATE-OF-THE-ART

BREATHERS.

NEWREGS

WOULDN’T IT BE NICE TO DEMO every new regulator before

committing your hard-earned cash? It is, after all, the most important

piece of gear you’ll buy, which puts a lot of pressure on making the

right decision—and that’s where ScubaLab comes in.

We invited all major manufacturers to submit their new regula-

tors (introduced within the last 12 months) for this review. After

inspecting them and reviewing the owners’ manuals we put them

on an ANSTI breathing simulator to measure the precise breathing

resistance a diver will encounter at four different depth/breath-

ing rate settings that range from normal breathing at 132 feet to

extreme exertion at 198 feet. Then we turned the regs over to a

team of eight test divers to be your stand-ins. Their mission was to

rate each reg using a 1 to 5 scale in seven ergonomic performance

categories, from ease of breathing to comfort features. These divers

also made notes on each reg—what they liked and what they didn’t

like. We then polled our test divers to find out which reg in each

price category offered the best combination of features, comfort

and performance and awarded these regs the additional honor of

being named a ScubaLab Testers’ Choice (see “Testers’ Choice &

Best Buy,” p. 73).

The complete results of all our tests are found in the charts on p.

98, and are summarized in the following reviews, which are presented

here in alphabetical order within price categories.

SCUBALAB ONLINE

For more on how

ScubaLab tests regula-

tors, including a detailed look at

how we use the ANSTI machine,

go to www.scubadiving.com/

bonus_2007_reg_test

S C U B A L A B ® R E V I E W E D

BY BILL KENDIG

PHOTOGRAPHY BY JOSEPH BYRD

R E G U L A T O R S O V E R $ 5 0 0

JULY 2007 S C U B A D I V I N G . C O M 73

PROS: Perfect simulator scores; well-designed

user adjustments; built-in electronic intermediate

pressure gauge; reversible hose configuration.

CONS: High price; large first-stage (XTX50

Status).

F IRST STAGE: These are the first regs to

feature a built-in electronic intermediate pres-

sure gauge, complete with an LCD screen that

indicates if the pressure is “HI,” “LO” or “OK”

before every dive. The electronics also track the

date and hours of use to indicate when it’s time

for routine service. Beneath the digital brain

are two different versions of an over-balanced,

environmentally sealed diaphragm first stage

that has plenty of brawn. Both regs offer four

low-pressure ports and two high-pressure ports

for convenient hose routing (low-pressure ports

are on a rotating turret on the XTX50; angled

on the XTX200). Both regs come factory ready

for nitrox mixes up to 40 percent. The XTX50

first stage comes in a bigger, bulkier package,

while the more streamlined XTX200 first stage

is available with a DIN connection.

SECOND STAGE: The pneumatically bal-

anced second stages are identical except for a

few cosmetics—the XTX200 has chrome trim,

the XTX50 does not. Well-designed adjustments

include a large control knob with a wide range

of travel for taking breathing resistance right

to the edge of cracking effort, and a ratcheting

venturi lever that lets you tune out freeflows.

Both second stages also feature a reversible

hose configuration.

TEST DIVERS SAID: The large ratcheting

venturi and the adjustment knob are easy to

find and use, even with gloves. Many test divers

also liked the Comfo-Bite mouthpiece. Clearing

was easy and the purge button was effective

without blasting fillings loose. Breathing was

very dry in all positions, and there was no drop

in performance in various positions.

THE ANSTI REPORT: Both regs aced the

breathing machine panel with a remark-

ably stable performance regard-

less of depth or demand.

P R I C E : $847 for the XTX50

Status; $990 for the XTX200

Status.

A P E K SXTX50 Status and XTX200 Status

72 S C U B A D I V I N G JULY 2007

A P E K SXTX200 Tungsten Swivel

P R O S : Perfect simulator

scores; well-designed user

adjustments; great hose swiv-

el connection on the second

stage; cool-looking protec-

tive finish.

CON: High price.

F I R S T S TA G E : This

compact, environmen-

tally sealed, over-balanced

diaphragm first stage is the

flagship regulator for Apeks—and it looks really

cool to boot. The hardened tungsten PVD finish

is not just for show, it also protects the reg from

the elements. Four low- and two high-pressure

ports are angled for comfortable hose routing

and there’s a brass plaque affixed to the first

stage for a distinct appearance. It’s nitrox-ready

right out of the box for mixes up to 40 percent

and shares the same smooth-breathing perfor-

mance as the regular XTX200.

SECOND STAGE: The Tungsten finish is

also found in the grill of the second-stage cover

and on the adjustment knob. It has all the same

adjustment features found on the other XTX

second stages, plus it comes standard with

a great new hose swivel connection that test

divers loved.

TEST DIVERS SAID: “It felt like the hose

wasn’t even attached,” wrote one test diver

commenting on the swivel connection. As with

the other XTX second stages reviewed here,

the large control lever and adjustment knob

were also a hit.

THE ANST I REPORT: Another perfect

score. The addition of the swivel made no sig-

nificant difference in breathing performance.

PRICE: $965.

A Q U A L U N GKronos

PROS: Compact first stage; simplified user

adjustments; unique side-venting exhaust tee;

ACD dam on first-stage inlet.

CON: Not environmentally sealed.

F IRST STAGE: The Kronos balanced-dia-

phragm first stage offers a full contingent of four

low-pressure and two high-pressure ports, giv-

ing you more flexibility in hose routing and the

option to use both a transmitter and pressure

gauge hose. The first-stage opening features

Aqua Lung’s Auto-Closure Device (ACD), which

closes the inlet to water intrusion whenever the

reg is off a tank. Another nice touch: The yoke

knob is covered with soft rubber for an easier

grip with wet hands.

SECOND STAGE: The new Side-X exhaust

system on the Kronos pneumatically balanced

second stage directs all bubbles to the diver’s

right for clearer viewing. An added benefit is

that warm air passes over the second stage valve

and hose, fighting freeze-up in cold water. The

new Dual Cam control simplifies adjustment by

combining the venturi and breathing resistance

knobs into one easy-to-find lever. While the

range of adjustment is small, it does the job of

stopping freeflows at the surface and fine-tuning

breathing performance underwater. The Kronos

comes with both a Comfo-Bite mouthpiece and

a standard spare.

TEST DIVERS SAID: “The Dual Cam lever

was glove-friendly and prevented surface free-

flows,” wrote one test diver, echoing the com-

ments of the others. Our divers also gave the

Side-X exhaust system a unanimous thumbs-

up. The compact second stage was an easy

breather, stayed dry in all positions and was

easy to clear.

THE ANSTI REPORT: Work of breathing

scores fell into the Excellent category for the

test that most closely represents recreational

diving and the Very Good category for the more

extreme tests. Close inspection of the breathing

loops shows that in these high-volume breath-

ing situations and at depths to 198 feet, the

reg’s inhalation effort was very stable while the

exhalation effort increased only slightly as the

tests got more challenging.

PRICE: $569.

Q: What is a ScubaLab Testers’ Choice?

A: We award the Testers’ Choice logo to the

gear that our team of divers vote as their

favorite combination of fit, features and perfor-

mance based on their extensive in-water use.

Q: How do you determine Testers’ Choice ratings?

A: While in the past we used a complicated points-based system to

determine what gear earned our coveted Testers’ Choice rating, for

2007 we simplified the process. At the conclusion of our in-water

testing, we divided the regs into their respective price groups and

polled our test divers with one final question: “Which one would

you buy?” It’s fascinating to see the wheels turning as each test

diver calculates all the pros and cons and comes up with their indi-

vidual answers.

Q: Does not earning a Testers’ Choice mean gear

is substandard?

A: Not at all. As you can see from the individual reviews and the

charts on p. 98, every regulator tested performed admirably on

the breathing machine, and all were able to stand up to the most

punishing tests. In the ergonomic evaluations, the lowest score test

divers gave any reg in any category was a Good rating. The results

of each review stand on their own and should be read carefully and

completely. Testers’ Choice is merely an additional tool to help you

analyze the results and make an informed buying decision.

Q: What is a ScubaLab Best Buy?

A: While Testers’ Choice is based on the vot-

ing of test divers, Best Buy is awarded at the

discretion of the ScubaLab staff. We award

this logo to the gear that we think is a particu-

larly good combination of performance and price.

Testers’ Choice & Best BuyA:

gear that our team of divers vote as their

favorite combination of fit, features and perfor-

mance based on their extensive in-water use.

A:

ing of test divers, Best Buy is awarded at the

discretion of the ScubaLab staff. We award

this logo to the gear that we think is a particu-APEKSXTX50 Status

APEKSXTX200 Status

R E G U L A T O R S O V E R $ 5 0 0

JULY 2007 S C U B A D I V I N G . C O M 75

PROS: Lowest overall work of breathing; corrosion resistance at a lower cost than titanium; great

second-stage swivel for added comfort.

CON: High price.

FIRST STAGE: The ST1 is a balanced-piston first stage turned from 316 stainless steel that offers

greater strength and corrosion resistance than brass regulators at a significantly lower cost than

titanium. It offers four low-pressure ports on a swivel turret with a fifth port on the end of the first

stage for easy hose routing, plus two high-pressure ports.

SECOND STAGE: The ST1 delivers high performance with a dose of comfort thanks to a

well-designed mouthpiece and Atomic’s Comfort Swivel. It also features all the usual Atomic

features—Automatic Flow Control (AFC), a self-adjusting venturi effect that increases breathing

performance as you descend; the Rapid Adjustment Knob, which allows the user to de-tune the

reg for surf entries or octopus use; a flexible purge cover; and the Seat Saving Orifice, which helps

maintain the reg’s peak performance over time. Inside the second stage, the entire valve body and

lever of this pneumatically balanced second stage is made of corrosion-resistant titanium.

TEST DIVERS SAID: Divers thought the ST1 was one of the “smoothest breathing” regulators of

the bunch and gave it the highest ergonomic scores of all the regulators in this review. The comfort

swivel helped boost comfort scores and test divers had praise for the user control knob and soft

purge cover. This reg also received the highest score for Ease of Breathing and was the only reg

rated Excellent by test divers for dryness. When we polled our test divers for their top reg in the

price category, the ST1 was a clear Testers’ Choice (see “Testers’ Choice & Best Buy,” p. 73).

THE ANSTI REPORT: While several regs in this review earned perfect breathing machine

scores on our 1 to 5 scale, the ST1 can boast the lowest overall work of breathing in every one of

our ANSTI tests.

PRICE: $899.

AT O M I C A Q U AT I C SST1

D I V E R I T EHurricane

P R O S : Compact tech-friendly reg; well-

machined user adjustments; dry breather in

all positions.

CON: Mouthpiece too small for some.

FIRST STAGE: The new Hurricane from Dive

Rite is a cyclone of air in a small package. The

first stage is an over-balanced diaphragm that

is cold-water-ready down to 36F, nitrox-com-

patible up to 40 percent, and comes standard

with a DIN connection. Angled ports put hoses

where you want them with two high-pressure

and four low-pressure fittings. A bright red

cap protects the first stage against overhead

scrapes and aids in diver recognition.

SECOND STAGE: The pneumatically bal-

anced second stage offers multiple adjust-

ments to fine-tune your dive. A large red

venturi control lever puts a stop to surface

freeflows and is easy to use with gloves. The

breathing resistance knob offers a wide range

of adjustment to dial in your preferred flow as

you descend. A comfortable mouthpiece and

a wide exhaust tee are a nice touch.

TEST D IVERS SA ID : Breathing adjust-

ments were “smooth and effective,” offering

“a well-machined feel.” Our test divers also

said the reg clears easily with a powerful purge

action. The wide exhaust tee did a nice job

of directing bubbles away, and breathing was

dry in all positions. The venturi control lever

prevented surface freeflows and opened up

nicely underwater. While the mouthpiece is

soft and comfortable, it was a little small for

many of the testers.

THE ANSTI REPORT: The Hurricane deliv-

ered an Excellent performance in the test that

most closely replicates recreational diving and

Very Good scores in the more extreme tests.

PRICE: $599.

R E G U L A T O R S U N D E R $ 5 0 0

PROS : High performance at a reasonable

price; new tri-material first-stage valve; proven

diver-friendly design.

CON: Narrow exhaust tee allows some bubble

interference.

FIRST STAGE: The Proton 12 Metal has been

one of Mares’ best breathing, balanced-dia-

phragm regulators for years, and it’s still going

strong. What’s new is the “tri-material” first-

stage valve, made of brass and two different

polyurethane compounds. It’s designed to last

longer and perform better than previous ver-

sions. It also has the Dynamic Flow Control fea-

ture, a dedicated low-pressure port that helps

deliver big air to your primary second-stage

hose for easy breathing.

SECOND STAGE: The Proton Metal is the

smallest second stage in this test group, and

its solid metal construction makes this reg well

suited to cold-water diving. The Vortex Assisted

Design (VAD) directs air to the diver through a

bypass tube from the valve seat to the mouth-

piece. The large front-cover purge is smooth

and easy to find, even with gloved hands. The

orthodontic mouthpiece is soft and comfort-

able and the exhaust tee follows the shape of

the regulator, but allows greater-than-average

bubble interference.

TEST DIVERS SAID: It’s hard not to like a

light, compact and easy-to-use reg. The Pro-

ton Metal delivers easy, dry breathing without

the need for user adjustments, and the reg is

comfortable in the mouth. All test divers com-

mented on the ease and function of the large

purge saying it was “smooth and powerful.”

THE ANSTI REPORT: The Proton Metal

earned Excellent breathing machine scores

across the board, another reason this regulator

is still going strong.

PRICE: $450.

M A R E SProton 12 Metal

O M SR250 High Performance

PROS: Environmentally sealed and rugged;

nice adjustment knob; easy clearing.

CONS: Small mouthpiece, some bubble inter-

ference.

FIRST STAGE: OMS uses an environmentally

sealed balanced-diaphragm first stage that is

tech-ready with a DIN connection and nitrox

capabilities up to 40 percent. This compact

performer provides four low-pressure and two

high-pressure ports, angled for easy routing.

SECOND STAGE: The R250 second stage

is light and offers user adjustments for venturi

and breathing resistance control. The large

adjustment knob can dial you right to the edge

of freeflow for crisp cracking effort. The Dive/

Predive venturi switch is easy to find—on top,

just in front of the mouthpiece—but it’s smaller

than most levers in this test group. The small

exhaust tee is streamlined, but didn’t wrangle

bubbles as well as others tested.

TEST DIVERS SAID: Testers said the regu-

lator was easy-breathing and dry in most posi-

tions. Some thought the mouthpiece was a

little small, but most liked the “huge range of

adjustment” the regulator had to offer. Clear-

ing was smooth and easy both by exhaling and

purging, though the front purge cover was “a

little stiff.”

THE ANSTI REPORT: The R250 earned

Excellent breathing scores at the first test point.

At greater depths and breathing

rates the regulator’s work of

breathing numbers fell into

the Good category across the

board.

PRICE: $418.45.


R E G U L A T O R S U N D E R $ 5 0 0


S C U B A P R OMK11/R395 and MK11/S555

PROS: Excellent performance at a budget price (MK11/R395);

compact first stage; nice second-stage adjustment; smooth and dry-

breathing in all positions.

CON: Some bubble interference.

FIRST STAGE: The MK11 first stage was the smallest of the test group

but held its own, putting up some of the best test scores recorded in this

review. This over-balanced diaphragm first stage features two high-pressure and four low-pressure

ports, two of which are marked “HFP” for pumping out 15 percent greater air flow. Convert to

a DIN connection and you have the makings of a compact tech rig. The big surprise is that the

MK11/R395 came in with the lowest price ($384) but with some of the highest performance, earn-

ing our Best Buy recommendation.

SECOND STAGES: The R395 second stage is light and simple with just the VIVA venturi to adjust.

It uses a large control knob in front of the mouthpiece that’s clearly marked “Dive/Predive.” Inside

the case are a new lever and diaphragm that are designed to reduce friction. The low-pressure

hose can be configured on either the right or left side to customize your rig and the flexible cover

allows for easy purging. The S555 second stage is pneumatically balanced, which translates into

lower cracking effort at depth. The case body and valve lever assembly are designed to prevent

freeze-up and it has the same excellent dive/predive switch as the R395.

TEST DIVERS SAID: Our divers found both regs to be smooth and easy breathers. The easy-

to-locate front purge covers were effective. The mouthpiece was comfortable for most while some

bubbles interfered with viewing in certain positions. Breathing was affected in certain head-up

positions with the R395, but not as much with the balanced S555 second stage. Both regulators

breathed dry in all attitudes. Most telling: test divers voted the MK11/S555 their Testers’ Choice

for regulators under $500.

T H E A N S T I R E P O RT: The

breathing machine loved these

regulators. Work of breathing was

Excellent in all tests, and the regs

turned in almost identical results.

PRICE: $384 for the MK11/R395

and $489 for the MK11/S555.

SCUBAPROR395SCUBAPROSCUBAPRO

SCUBAPROS555

SCUBAPROMK11

S P E C I A L T YR E G U L A T O RS P E C I A L T YR E G U L A T O R

A P E K STek3 XTX50

PROS: Comes in right- and left-side

configurations for twin cylinders; envi-

ronmentally sealed; excellent breathing

performance.

CON: Port configuration is not favorable

for single-tank diving.

FIRST STAGE: The Tek3 first stage is

the first regulator designed specifically for

twin cylinders, offering one high-pressure

port and three low-pressure ports, all on

one side. Consequently, the Tek3 is made

in right- and left-hand versions. It is avail-

able in DIN or yoke configurations and

comes nitrox-ready up to 40 percent. It’s

over-balanced and environmentally sealed

for the most demanding conditions.

SECOND STAGE: The XTX50 second

stage is pneumatically balanced, with

significant user adjustments and offers

reversible hose configuration. The resis-

tance adjustment knob is large and offers

a wide range for fine-tuning. The indexed

venturi control lever lets you ratchet up

the flow on descent and block unwanted

freeflow on the surface. A wide exhaust

tee keeps bubbles out of view and can

be exchanged with a smaller one for use

as a streamlined octopus.

TEST DIVERS SAID: The Tek3 was a

smooth breather and dry in all positions.

User adjustments are “easy to find and

operate.”

T H E A N S T I R E P O R T: The Tek3

XTX50 received Excellent scores in all

breathing machine tests.

PRICE: $1,450 for the Tek3 Complete

set (left- and right-side Tek3 first stages,

two XTX50 second stages, a two-meter

hose, a standard hose and a regulator

necklace); $925 for a matched pair of

Tek3 first stages.

3REGULATOR FEATURES

OVER $500 PR

ICE

WA

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IN

1ST

STA

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PO

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2ND

ST

AG

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2ND

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APEKS XTX50 Statuswww.aqualung.com

$847 Ltd. Lifetime UK Over-Balanced

Diaphragm2 HP 4 LP

Pneumatically Balanced

Resistance Knob RVS* Up to 40%

APEKS XTX200 Statuswww.aqualung.com


Diaphragm2 HP 4 LP



APEKS XTX200 Tungsten Swivelwww.aqualung.com


Diaphragm2 HP 4 LP



AQUA LUNG Kronoswww.aqualung.com

$569 Ltd. Lifetime France Balanced

Diaphragm2 HP 4 LP


Dual-Cam†

(venturi/resistance) Up to 40%

ATOMIC AQUATICS ST1www.atomicaquatics.com

$899 Ltd. Lifetime USA Balanced

Piston2 HP 5 LP


Resistance Knob Up to 40%

DIVE RITE RG3500 Hurricanewww.diverite.com

$599 Ltd. Lifetime France Over-Balanced

Diaphragm2 HP 4 LP Balanced Resistance

Knob Venturi Lever Up to 40%

UNDER $500

MARES Proton 12 Metalwww.mares.com

$450 Ltd. Lifetime Italy Balanced

Diaphragm2 HP 4 LP Unbalanced N/A Up to 40%

OMS R250 High Performancewww.omsdive.com

$418.45 1 Year USA Balanced Diaphragm

2 HP 4 LP Unbalanced Resistance Knob

Dive/Pres-Dive Switch Up to 40%

SCUBAPRO MK11/R395www.scubapro.com

$384 Ltd. Lifetime Italy Over-Balanced

Diaphragm2 HP 4 LP Unbalanced VIVA** Up to 40%

SCUBAPRO MK11/S555www.scubapro.com

$489 Ltd. Lifetime Italy Over-Balanced

Diaphragm2 HP 4 LP

Pneumatically Balanced VIVA** Up to 40%

SPECIALTY REG

APEKS Tek3 XTX50www.aqualung.com

$1,450 (2 complete regs); $925 (LH and RH first stages only)

Ltd. Lifetime UK Over-Balanced

Diaphragm1 HP 3 LP



†Dual Cam (combines venturi control with breathing resistance control) * Reversible Venturi System ** Venturi Initiated Vacuum Assist

TEST DIVER RATINGS OF ERGONOMIC PERFORMANCE

ANSTI BREATHING SIMULATOR RESULTS

EA

SE O

F B

RE

ATH

ING

DIF

FER

EN

T P

OSI

TIO

NS

DIV

ES

DRY

BU

BB

LEIN

TER

FER

EN

CE

CLE

AR

ING

B

LOW

/PU

RG

E

CO

MFO

RT

AD

JUST

MEN

TS

A >

37.

5 R

MV

@

132

fsw

B >

75

RM

V

@ 1

32 f

sw

C >

62.

5 R

MV

@

165

fsw

D >

62.

5 R

MV

@

198

fsw

4 4 4 4 4 4 4 5 5 5 5

5 4 4 4 4 4 4 5 5 5 5

5 4 4 4 4 4 4 5 5 5 5

4 3 4 5 4 4 4 5 4 4 4

5 4 5 4 4 4 4 5 5 5 5

4 4 4 4 4 4 4 5 4 4 4

4 3 4 3 4 4 N/A 5 5 5 5

4 3 4 3 3 3 3 5 3 3 3

4 3 4 3 4 4 3 5 5 5 5

4 3 4 3 4 4 3 5 5 5 5

4 4 4 4 4 4 4 5 5 5 5

Rating System: 5=Excellent 4=Very Good 3=Good 2=Fair 1=Poor

98 S C U B A D I V I N G JULY 2007 JULY 2007 S C U B A D I V I N G . C O M 99

I N D E P T H

How We Test RegulatorsANSTI Breathing Simulator The ANSTI machine is the international industry

standard for scientifically evaluating a regula-

tor’s performance. It measures a regulator’s

work of breathing (WOB) in joules per liter (j/l)

for each complete inhale/exhale cycle. We test

regulators at four different RMV/depth com-

binations (RMV stands for Respiratory Minute

Volumes, basically the amount of gas that can

be ventilated through the lungs in one minute).

All simulator tests are performed at a supply

pressure of 725-760 psi. If a regulator can per-

form well at this supply pressure, it will perform

as well or better at higher supply pressures.

Here are the tests and what they represent:

» COLUMN A 37.5 RMV @ 132 fsw. A some-

what aggressive breathing rate at the maxi-

mum recreational diving depth. A physically

fit recreational diver might breathe at this rate

while swimming a long distance. (A relaxed

diver on a drift dive will probably be breathing

at 22 RMV or less.) A diver could theoretically

maintain 37.5 RMV for five minutes or longer

without becoming significantly winded.

» COLUMN B 75 RMV @ 132 fsw. An extreme-

ly aggressive breathing rate at the maximum

recreational diving depth. A diver in excellent

condition can breathe at 75 RMV for about one

minute. This test represents how a reg might per-

form with a single diver breathing at an extremely

heavy work rate. It also serves as a loose simula-

tion of the stress a reg would be under if two

divers were breathing off the same first stage in

an air-sharing situation. Only the U.S. Navy and

ScubaLab use this breathing rate to help identify

the outer limits of a reg’s performance.

» COLUMN C 62.5 RMV @ 165 fsw. All regs

sold in the European Common Market must

pass a test standard known as EN250, which

uses this RMV/depth as its benchmark. For this

reason, it’s also the depth and breathing rate

most commonly used by manufacturers to test

regulators. This is a very aggressive breathing

rate. A recreational diver in excellent condition

chasing a bat ray through open water would

probably be able to maintain 62.5 RMV for only

a few minutes.

» COLUMN D 62.5 RMV @ 198 fsw. This is the

U.S. Navy’s Class A test depth and breathing

rate, although we use a lower supply pressure

(725-760 psi). We conduct this extreme test (no

diver should ever be breathing this aggressively

at this great a depth with this little air left in

his tank) to explore the outer limits of a reg’s

performance.

Our test parameters state that the highest

inhale or exhalation pressure experienced by

the “diver” should never exceed 25 millibars

or a total WOB of 3 j/l. If a reg exceeds either

parameter, it “fails” our test, but that doesn’t

mean that it stops delivering air—only that the

breathing resistance at some point in the cycle

is higher than what is common for most mod-

ern regulators.

A machine as accurate as the ANSTI simu-

lator can accurately differentiate j/l measure-

ments to tenths and even hundredths of a

point. Human divers, however, can’t. For the

sake of simplicity, we translate j/l measure-

ments into scores on a 2 to 5 scale as follows:

5=EXCELLENT: A total WOB of 1.05 j/l or

less.

4=VERY GOOD: A total WOB of 1.06 to

1.55 j/l.

3=GOOD: A total WOB from 1.56 to 2.25 j/l.

2=FAIR: A total WOB of 2.26 to 3.0 j/l.

Ergonomic Tests: The Human FactorBreathing machines tell only half the story. To

gauge the ergonomic traits of regulators, we

use a minimum of six test divers. Each diver rates

each reg for user-friendliness in seven areas:

» EASE OF BREATHING: How well a regu-

lator delivers air in the standard swimming

position.

» DIFFERENT POSITIONS: How the regula-

tor breathes when the diver is in a heads-up or

face-down position.

» DRYNESS: Does the regulator breathe wet

or dry in both a normal swimming position and

odd swimming positions?

» BUBBLE INTERFERENCE: Considered

while looking down, straight ahead, up at a

45-degree angle and straight up.

» EASE OF CLEARING: Divided into two

parts: 1) How easy is it to find and use the

purge button, and how forceful is the purge?

2) How much force is required to clear the regu-

lator using the blowing method?

» COMFORT: Test divers rate the comfort of

the mouthpiece, the feel of the second stage in

the mouth, hose lengths and stiffness.

» ADJUSTMENTS: Are adjustments easy to

find, grip and turn? Do they do their job in a

reasonable manner?

Performance is recorded using both numeric

scores on a 1 to 5 scale (5=Excellent, 4=Very

Good, 3=Good, 2=Fair, 1=Poor) and written

comments.

ATOMIC AQUATICS ST1www.atomicaquatics.com

SCUBAPRO Mwww.scubapro.com

SCUBAPRO MK11/R395www.scubapro.com

Documents

scubalab reviews state-of-the-art breathers - Atomic Aquatics