was known as the economy regulator company of its day. In August of
1962 Healthways wanted to create a professional line of equipment and
hired Dick Bonin and Gustave Della Valle to create this line. They
chose the name SCUBAPRO for this upgraded or professional line.
was in financial trouble and declared bankruptcy on December 26, 1962,
only four months after hiring Dick and Gustave. Dick and Gustave
decided to begin their own company and purchased the name SCUBAPRO from
Healthways for $1.00.
1974 Dick sold the company to the Johnson’s Wax Company for $11
Million. Johnson's Wax is now called the S. E. Johnson Company and the
outdoor division is Johnson Outdoors. Dick Bonin stayed with SCUBAPRO
as President of the company until his retirement in 1997.
FIRST STAGE REGULATORS
The MK 1
was not the first regulator that was produced by SCUBAPRO. It was
developed during the time when Dick Bonin and Gustave Della Valle were
working with Healthways. The piston is a balanced flow-thru design that
is still used today.
regulator was on the market from 1964-1977. The MK 1’s performance at
deeper depths is superior to the MK 2. It has a rounded bottom with a
single low pressure port and one high pressure port. The yoke is the
smallest of the three yoke sizes that SCUBAPRO has offered. This small
yoke design should only be used with a tank that holds a maximum of 2250
The MK 2
is actually the first Regulator that was purely SCUBAPRO. It was
introduced in 1963, the first year of SCUBAPRO, and is still offered now
with only a few modifications.
regulator is without a doubt the most dependable first stage in the
world. It is a standard piston design. The original, 1963-1971, has a
small yoke with a wing nut and a rounded bottom. It had two low
pressure ports and one high pressure port.
second generation, 1972-1977, has a flat bottom, with the small yoke,
wing nut and two low pressure ports and one high pressure port.
third Generation, 1978-1980, also has a flat bottom, three low pressure
ports, one high pressure and S.P.E.C. ambient pressure ports. The
S.P.E.C. cap can be identified by very small ambient port holes. There
was an optional S.P.E.C. rubber boot available.
fourth generation was available from 1993-1995. The S.P.E.C. cap had
now been removed. It has three low pressure ports, one high pressure
port, large yoke and the wing nut has been replaced by a black knob with
SCUBAPRO molded into it.
fifth generation, 1996-1997, has four low pressure ports, one high
pressure port, large yoke, and black knob with a sticker that said MK 2
on it and a rubber boot bumper on the cap.
sixth generation, 1998-present, has a MK 2 Plus sticker and a rubber
bumper over the regulator cap it also has a matt finish. There was also
an accessory called the environmental cap for the early MK 2 first
stages. This cap replaces the standard cap for the MK 2 and is bulbous
The MK 200
is a slightly different version of the MK 2. It has a piston head that
is slightly larger than the MK 2. It was on the market from
1988-1992. The MK 200 has three low pressure ports, one high pressure
port, a large yoke and black knob that have a MK 200 sticker. There
were two versions. The first version, 1988-1991, has an S.P.E.C. cap.
An optional rubber S.P.E.C. boot was offered for this regulator and
would also fit the end cap of a MK 2 first stage. In 1992 the S.P.E.C.
cap was removed.
The MK 3
was available from 1964 – 1987 and can be considered to be a baby MK2.
The main identifier is internally. The piston head of the MK 2 is
about the size of a quarter and the MK 3 piston head is the size of a
first generation, 1964-1965, has a small yoke, wing nut, flat bottom,
two low pressure ports and one high pressure port. The second
generation, 1966-1981, is the same except the bottom is now rounded.
The third generation, 1982-1987, has three low pressure ports, one high
pressure port, a flat bottom, large yoke, wing nut and an S.P.E.C. cap.
The MK 4 did not exist as a first stage on its own. It was sold in Europe as a combination MK 5 with the 108HP second stage.
The MK 5
revolutionized the first stage with its flow-thru piston design. It
was so popular that it was on the market for 25 years, 1965-1990.
MK 5 provided a consistent flow of air to the second stage at any
depth. It truly is the first high performance first stage regulator in
the industry. The MK 5 is the first regulator to offer the consumer a
swivel. It is also considered one of the most dependable first stages
first of the MK 5’s, 1965-1977 has one high pressure port and two low
pressure ports on the swivel and has a small yoke and wing nut. The
second generation, 1978-1979, is the same as the first with the
exception of the addition of a four port low pressure swivel and a bit
heavier yoke. The third generation MK 5, 1980 only, added three
modifications. The first is an even heavier yoke and the second is the
addition of an S.P.E.C. cap All of the previous MK 5 regulators have an
optional Environmental Cap for cold water diving that is bulbous in
appearance. The third modification is the addition of a second High
pressure port. The fourth generation, 1981-1985, added a fifth low
pressure port. The fifth MK 5 first stage, 1988-1990, is the same as
the fourth generation, but, it has a black knob with a sticker that says
MK5 instead of a wing nut being added.
sixth version of the MK 5 was produced in Sweden for a short period of
time. This version had a totally different swivel and swivel retainer.
1981 SCUBAPRO made an accessory that could be added to the first
stage. The device was called the "Sonic Adapter” and its purpose was to
give the diver an audible alarm when their air dropped to around 600
PSI. It was only made this one year.
MK 5 external design is the most copied by manufacturers around the
world, yet they never achieved the performance that the original has.
The MK 5 is still being used by many divers to this day.
The MK 6 is
simply another version of the MK 5. It was on the market from
1969-1972. The only difference that it had from the MK 5 is that the
yoke was pneumatically attached to the tank valve as opposed to the Yoke
Screw. The MK 6 had a swivel like the original MK 5 with two low
pressure ports and one High Pressure port. A second version of the MK 6
has a yoke nut and a beefier mid-sized yoke. This new yoke design
could be replaced with the standard yoke design if the consumer desired.
The MK 7
was available from 1971–1987 and has the most unique appearance of any
SCUBAPRO regulator. The MK 7 is the only SCUBAPRO regulator that has a
fixed non-swivel yoke. It is very large and heavy and has the feature
of an audible alarm when your tank pressure dropped to around 600 PSI
which could be adjusted to the individual divers needs. When your air
got to this point the regulator would vibrate to cause a honking sound.
This honking earned the regulators the nick name "The Honker”. The
piston of this first stage is exactly the same as the MK 5.
are three generations of the MK 7 and each can be identified by the
size of the yoke. The original, 1971-1977, has the small yoke. The
second generation, 1978 only, has a medium size yoke and the third
generation, 1980-1987 has the heaviest yoke. All three generations have
a wing nut, one high pressure port and two low pressure ports.
The MK 8
is again another version of the MK 5. It was on the market from
1979-1982. There are three versions. The primary difference from the
MK 5 is that it did not have a swivel. The first generation, 1979-1980
has a small yoke, wing nut, with one high pressure port and one low
pressure port and the cap has a rounded appearance. The second
generation, 1980 only, has a rounded bottom with one low pressure port
and two high pressure ports. The third generation, 1981 only, has a flat
bottom, three low pressure ports and two high pressure ports. We have
not been able to locate a production model of this version. It is
pictured in the 1981 catalog, but no one seems to remember it actually
making it to the market in the USA. Please contact us if you have one
of these regulators or any documented information on this MK 8. The
fourth generation, 1982 only, has 2 high pressure ports and 4 low
pressure ports with an S.P.E.C. cap. All of the MK 8 first stages have a
The MK 9
came onto the market in 1983 and was available to purchase through
1985. This is a totally new design by SCUBAPRO. The piston head is
considerably smaller than the MK 5 piston head and the piston travels
entirely in the regulator body. You can tell the difference by the
placement of the ambient ports. On the MK 5, the ambient ports are on
the cap while the MK 9 has the ports on the regulator’s upper body and
the MK 9 does not have a swivel The MK 9 has a large yoke, wing nut,
five low pressure ports and two high pressure ports.
The MK 10
is an upgraded version of the MK 9. The difference is that a swivel
was added to the MK 9. It was available from 1984-1995. The first
generation MK 10, 1984-1995, can be identified by the large yoke and a
wing nut. The second generation, 1988-1989, changed the wing nut to a
knob with a sticker that said MK 10, which is common place today. The
third generation, 1990-1994, the ambient ports were changed to the
S.P.E.C. An optional S.P.E.C. kit could be added so that an
environmental silicone could be added to enhance the performance in
colder water. The kit came with a black rubber boot and environmental
people confuse the MK 10 with the MK 5. The sure fire way to
distinguish them apart is the location of the ambient ports. The MK 5’s
ambient ports are located on the piston cap located in the center
section of the regulator and the MK 10’s are located on the upper main
body as it is in the MK9. This regulator was paired with the world
famous G250 second stage and became one of the most popular first stages
in history. All MK 10 regulators have two high pressure ports and five
low pressure ports on its swivel.
The MK X, not MK 10,
regulator was sold in Europe as a combination only. The Mark X is a MK
10 first stage paired with a "balanced” 109 second stage. In the USA
this was known as the Balanced Adjustable. It was sold as The MK X Dual
Balanced regulator system. This is marked on the metal cover of the
The MK 10 PLUS
was a first step of transitioning first stage regulators from the MK 10
to the MK 20. It was on the market from 1996-1997. SCUBAPRO placed a
bushing on the piston along with a silicone sleeve that assisted in
making the piston more cold water proof. The MK10 Plus could handle tank
pressures up to 4000 PSI. The knife edge on the piston was also
redesigned to a more rounded feel and the concave seat was replaced with
a seat with a flat bottom. The only external distinguishing items are
that the yoke knob had MK 10 PLUS on the end cap and the seat retainer
was satin chrome.
MK 10 Plus also had an optional Nitrox kit. The Nitrox version has a
Yellow sticker with green printing on the yoke knob, a green saddle
between the yoke and the body and a yellow sleeve instead of the black
that came on the original. The MK 10 Plus, like the MK 10, had two high
pressure ports and five low pressure ports on its swivel.
The MK 15
was originally designed to handle tank pressures up to 4000 PSI. It
has a new and larger piston head than the MK 10 or MK 10 Plus. The MK
15 has small ambient ports, a matte finish, rubber sleeve located
between the swivel and the piston cap, five low pressure ports, two high
pressure ports, a large yoke and a yoke knob as opposed to a wing nut.
are only two versions of the MK 15 as it was only on the market from
1994-1995. The first version, 1994 only, can be identified by the seat
retainer. The first version, and the rarest, has a slot for an Allen
key for removal of the seat retainer and the second version of the seat
retainer has two pin holes. The second version, 1995 only, also has an
upgraded high pressure seat. Both versions of the MK 15 have two high
pressure ports and five low pressure ports on its swivel.
The MK 20 TIS
was on the market from 1996 – 2001. This new flow thru piston design
with its large composite piston head and low friction bushings enhanced
reactivity by reducing friction thereby improving the flow rate to over
300 cubic feet of air per minute. This became the most high performance
regulator in the entire dive industry. The plastic bushing system
insured that the piston would align perfectly each time the knife edge
would strike the seat.
piston itself went through four modifications during its tenure. The
original piston had a single o-ring on the piston head with a low
friction square shaped ring and an all stainless shaft with a rounded
edge on the seating end. The second piston was changed to a chrome
plated brass with the tip remaining uncoated. The third modification is a
full stainless steel piston head with a single o-ring held in between 2
square shaped low friction rings. The fourth version is a composite
head with two o-rings and a stainless shaft with an enlarged rounded
edge creating a smaller surface contact area, but still retaining the
rounded edge detail.
main spring also has a polyurethane coating to prevent ice crystals
that may cling to the spring coils during cold water diving. This was
done as a means to prevent freezing up. This system was called the
"Thermal Insulating system” or T.I.S.
are three versions all coming on the market at the same time. The
Brass version, 1996-2001, has a matte finish with a rubber sleeve around
the body, a black knob with black sticker with MK 20 written on it.
This version also has a black saddle with three slits in it. This
saddle was later replaced with a saddle that only has two slits after an
upgraded yoke retainer was installed.
second version, 1996-1999, is a Nitrox regulator. This regulator can
be identified by the yellow sticker with MK 20 Nitrox printed in green
on it, a green saddle and a yellow rubber sleeve on the body. The first
MK 20 Nitrox had a brass piston with a green piston head bushing. The
MK 20 Nitrox was oxygen cleaned. SCUBAPRO stated that this oxygen
cleaned regulator should never be used with 100% oxygen. They also felt
at this time that any SCUBAPRO regulator that is exposed to oxygen
mixtures above 23.5% should be oxygen cleaned and compatible.
final version was the MK 20 UL for ultra-light. It has a black body
and the internal walls are polyurethane coated. The original piston was
also made of aluminum with Teflon coating on the shaft with the tip
being uncoated. The regulator body was made of anodized aluminum
magnesium alloy Teflon coated. The black body had two different looks;
the black aluminum is the original, 1997-1999, and the brownish/black
body came in 2000. Like many of its predecessors, the MK 20 has two
high pressure ports and five low pressure ports on its swivel.
The MK 25 came
into the market in 2002 and the first version was called the MK 25
T.I.S. (Thermal Insulating System), 2002-2003. It is made from brass
and its appearance is very similar to the MK 20. The primary change was
the Seat retainer. In the MK 20 it was removed with an Allen key and
on the MK 25 it can only be removed with a socket. In the center of
this cap is an adjustment screw. This adjustment screw enabled the
technician to adjust the intermediate pressure of the first stage from
the outside. The MK 25UL, 2002 only, has a black aluminum body. The MK
25’s Thermal Insulating System is exactly the same as the MK 20.
The MK 25T,
2002-present, is mechanically the same as the MK 25 T.I.S. It also
appears the same. The only difference is that the body is made of
titanium instead of brass. There are two versions of the MK 25T; the
first version, 2002-2003, had the cap design of the MK 25T.I.S. and the
second version, 2004-present, had the finned cap design of the MK 25
The MK 25 AF, 2004-present, added a finned cap. These fins are designed to dissipate cold generated during pressure reduction and warm up the first stage to improve, even more, the anti-freeze characteristics of the MK 25. The MK 25 SA,
2004-2006, which is again mechanically the same as the MK 25AF, has the
swivel and seat retainer made of stainless and the body aluminum. The MK 25 TI
came on the European market in 2002. This regulator is also
mechanically the same as the MK 25 AF with a black aluminum body and a
titanium swivel. In 2009 the MK 25AF came out with a new highly polished
body instead of the matte finish. It was only available in combination
with the newly introduced A700 second stage. All MK 25 models have two
high pressure ports with five low pressure ports located on its swivel.
In 2009 a highly polished version of this model was offered in
combination with the new all metal A 700 second stage.
THE BALANCED DIAPHRAGM REGULATORS
The MK 14
was on the market from 1998-2000. This was SCUBAPRO's first ever
diaphragm regulator. SCUBAPRO decided to enter this market because
there are many divers around the world, especially in Europe, that
preferred this type of regulator for cold water diving. The yoke knob
was marked with a sticker stating that it is a MK 14 and it had two high
pressure ports and 5 Low pressure ports on the swivel.
In 1999 the MK 18
was introduced and remained on the market through 2001. The MK 18 is
the first proprietary diaphragm design. The MK18 was a bit more high
performance than the MK 14 and was offered in two versions.
The first version 1999-2000, is the MK 18 UL
and was black in color. The second version, 2001 only, is the standard
brass version. There are two different looks to the UL. The first is a
black body and cap and the second, 2001 only, has a brownish black
coloration. The MK 18’s swivel is tapered down from the body, were as
the MK 14’s swivel is beefier and about the same size as the regulator
cap. The yoke knob had a sticker indicating that it is a MK 18. The MK
18 has two high pressure ports and five low pressure ports on its
The MK 16,
another entry into the diaphragm regulator market, was on the market
from 2001 through 2005. In reality it was still being sold through 2009
as a special sale regulator with an upgrade kit installed and an R190
second stage attached. The MK 16 has all the same internal parts as the
MK18. There were two versions the first, 2001-2003, had a large rubber
cap over the regulator cap and the second version, 2004-2005, had a
more compact rubber ring. The MK 16 had two high pressure ports and
four low pressure ports.
The MK11 along with the MK17
were brought to the market in 2006. These diaphragm regulators were
the first on the market that could be considered high performance.
These regulators could handle flow rates up to 250 cubic feet of air per
MK11 is a very compact first stage with two high pressure ports and
four low pressure ports. The yoke knob has a sticker on it designating
it as a MK11. A titanium version was added in 2009. SCUBAPRO Japan
also introduced a MK11 T White in 2009. This regulator is exactly the
same as the USA version with the exception that the knob is white and
the two boots on the regulator main body are also white. This was
paired with an S555 that has a white insert and a white Vinturi
MK17 is slightly different than the MK11 on the inside. The major
difference is the addition of a totally dry ambient chamber that is
completely environmentally sealed ribbed end cap with a unique dual
diaphragm system to read the ambient pressure. The function of this cap
is to keep out contaminated water and the ribs are designed to better dissipate cold generated during pressure reduction
to make the MK 17 even more cold water proof. The sticker also states
that it is a MK17 and it also has two high pressure ports and four low
was introduced to the European market in 2007. The MK19 is a MK17 that
has a swivel containing five low pressure ports. It was not available
in the Americas.
SPECIAL FIRST STAGE REGULATORS
The 24ct Gold Plated MK 10/G250 was
produced in 1991 as a special promotional regulator. There were only
300 produced commemorating the number one selling regulator in history.
were also several military version regulators produced over the years
for the Italian Navy. These regulators are all Black anodized chrome
plated brass and came in combinations of the MK 5/109 and MK 5/Balanced
The European market in 2007 introduced the MK2/295 Oxygen and the MK 25 S555 Oxygen.
These regulators are certified for use with 100% oxygen and can be
easily distinguished from the standard models by the Green front covers
on the second stages, green hose protectors, and green bumpers. These
regulators are EN 144.3 fitted and will not work in standard DIN 477
fitted tank valves. In 2009 SCUBAPRO AMERICAS offered an upgrade kit
for the MK 2 and the MK 25.