It was in 1945 that Commander Jacques-Yves Cousteau and engineer Émile Gagnan filed the patent for the COUSTEAU-GAGNAN diving suit.

It is then a device consisting of a reserve of portable compressed air (consisting of 1.2 or 3 aluminum bottles) equipped with a regulator on demand which is the centerpiece (Photo 1).

To launch its commercialization Air Liquide company will create a subsidiary: Spirotechnique SARL which will be born on May 26, 1946.


It is not until 1955 at the exit of the Mistral that the regulator will be considered as an element separable from the rest of the scuba. Divers will call it CG45 (abbreviation Cousteau-Gagnan 1945), a name that will remain until today.


This regulator will be marketed from 1946 to 1955 knowing that in 1955 it will be produced only in narghile version.

Indeed, the GC45 is the only double-hull regulator of the brand that is convertible into hookah and vice versa. It suffices for this to remove the mechanism of the first stage by condemning it with a plug provided for this purpose on the membrane side and then replacing the caliper by a low pressure connection or hookah pipe can be connected.


The typology and chronology of GC45.


I divided the GC45 into 2 types:

The archaic  CG45 (1946 - 1950) is the rarest.

The standard GC45 (1949 -1955) which is the most common.

The CG45 with archaic bowl


The GC45 with archaic bowl are recognizable by their fine tubes with a diameter of 20 mm and more particularly that of expiration which is bent at 45 ° (click on picture 2).

The reason is simple: on the first suits the regulator was mounted behind the bottle and this elbow allowed to bring the corrugated hose to the front without bending (click on Photo 3). Unfortunately, this positioning exposed the regulator to shocks during a fall and even more serious when diving, by subjecting the corrugated pipes to the rocks or the cutting plates of the wrecks ...

This configuration will be quickly abandoned to bring the regulator back between the plunger and the bottle to protect it, no longer needing to bend the exhalation tubing.

Photo 1
Photo 2
Photo 3

The archaic models are grouped in 3 versions:

The without manufacturer's label

The big label SARL

Small label SARL


They are distributed chronologically as follows:

The first CG45 without manufacturer plate.


At first (in 1946) the serial number was stamped directly on the expiration tray (Photo 4) and later on the back on the HP body (Photo 5) right next to the caliper, the regulators of this period dates from 1947 and 1948.

I only know 3 copies: the serial number 150, 516 and 568. This variant is very rare. These first regulators were sold with a FERNEZ metal end for the very first of 1946. In photo 6, the image presenting the regulator in the catalog of 1946.

Photo 4
Photo 5
Photo 6
Porfolio du N°568

The big plate manufacturer SARL


In 1948 appeared the first manufacturer's plate called big plate SARL.

There was probably a transition period alternating regulators with or without plate.

This assumption is based on the fact that I found the No. 537 (click on picture 7) with plate and No. 568 without plate but with the serial number stamped on the HP body.


The CG45 big plate SARL is marketed with a large rubber tip made by GODEL for Spirotechnics (Photo 8).

Note that the serial number 864 ends with the letter N. It is mounted in narghile so can be N for narghilé ....

(Photo 9 and 10)

This regulator would come from the arsenal of the East. We do not know the reason of the presence of this letter, however even if to this day it is the only big plate SARL known with this peculiarity one can suppose that a small series was published.

The biggest serial number of a CG45 big plate SARL known to date is the No. 1097 which means that a quantity of about 550/600 units was produced however my research allowed me to find some than 9 around the world, making it one of the rarest and most sought after collectors. In photo 11, the image showing the regulator in the catalog of 1948.

Mistral 005 copie.jpg
Photo 7
Photo 8
Photo 9
Photo 10
Photo 11

You will find in slide show the 9 big labels of private collections that I have found  around the world: the numbers 537 - 631 - 684 - 763 - 835 - 864N - 941 - 970 - 1097

(click to enlarge the photos)

The small plate manufacturer SARL


In 1949 appears the CG45 small plate SARL, it is declined in 2 variants:


-This with the archaic bowl that is still produced but the GODEL rubber tip is replaced by a straight metal tip Fernez type (Photo 11).


- With the first standard lunch box (Photo 12) with a configuration called PRO (professional). It was specially developed for the new constant volume garment developed by Spirotechnique: the PHOQUE suit (Photo 13).

On this bowl the tubes have a larger diameter since we go from 20 to 25mm knowing that the expiration is no longer curved. They have threaded connections soldered with tin which allow not only to equip the regulator of the famous tip PRO but also to easily disconnect the corrugated pipes at the bowl or the mouthpiece which remains attached to the hood of the seal garment. .

At present time the smallest serial number of a CG45 small known LLC plate is the No. 1137 and the largest No. 1871, an estimated production of about 750 to 800 units. In spite of that I have managed to register to date only about twenty units around the world.

An important detail, the first units with small plate SARL were mounted "to the big plate", that is to say vertically, the length of the plate perpendicular to the pipes (Photo 14). It is probably only from 1950 (around the serial number 1200) that the plates will be fixed horizontally (Photo 12). In photo 15, the image presenting the regulator in the catalog of 1950.

Photo 11
Photo 12
Photo 13
Photo 14
Photo 15

Slideshow of some CG45 in label version SA

(click to enlarge the photos)

The small plate manufacturer SA


In 1951, to meet the demand for the production of the Cousteau-Gagnan diving suit, the status of the Spirotechnique goes from SARL to SA.

We thus see a new small nameplate appearing with the mention SA LA SPIROTECHNIQUE.

The manufacture of the archaic bowl is abandoned in favor of a new variant in parallel with the standard version PRO, which I named standard version (Photo 16 and 17).

In appearance similar to the PRO it is identified by the absence of threaded connections to the tin on the pipes and by a new straight metal tip shorter than the Fernez type of 1949. This tip will be kept when exiting the regulator Mistral in 1955 and will be called later "endpiece D10" term taken from the reference of the Mistral standard catalog spirotechnique 1962.

I have found so far CG45 with small plate SA included between the serial number N ° 1960 to N ° 6194.

Photo 16

Slideshow of some CG45 in label version SA

(click to enlarge the photos)

Photo 17

These CG45s are divided into 2 groups:


The first group consists of regulators with serial numbers stamped with coarse numbers (to date including serial numbers N ° 1960 to N ° 5127)

There is mainly regulators mounted caliper because narghile versions were produced only on demand for professionals.

There are 2 variants:

A series produced in 1951, with at least 175 units bearing a serial number ending with the letter M (from serial number 2542M to 2717M with certainty). The meaning is unknown for the moment, but probably a series for the Navy. (Photo 18)


Another variant with at least 62 units of regulators will be produced in 1953 with the plate called "upside down" (Photo 19) (from the serial number 4166 to 4228 with certainty) This name comes from the fact that if one CG45 normally (tubing facing up) the plate appears upside down. This is not a factory editing error as I read on some discussion board. This series is intended to be rigged tubing down to increase the protection of rubber hoses (Possibly for caving use). Of course respecting this configuration the plate will appear at the place. This assembly will be even later taken by the Spanish manufacturer Nemrod on the black label Snark III regulator (Photo 20).

Photo 18
Photo 19
Photo 20
  • The second group of CG45 plate SA is a last series produced in 1955. It is probably composed of 1000 units comprising exclusively CG45 narghile having the particularity of having a low pressure elbow, unlike earlier hookahs which have a connection in the extension of the HP body.

  • In addition, their serial number is stamped with fine numbers like those used on Mistral regulators from 1957.

  • This assumption is based on my observations in private and museum collections, ranging from serial number 5206 to 6194 inclusive, knowing that the latter is the largest serial number known to date for a CG45 regulator.

  • We can therefore assume that the total production of CG45 amounts to around 6200 units ... How many remain? Hard to say but as I found 72 currently in private collections after a good decade of research I think that being optimistic there should not be more than 200/250 units worldwide.

Diaporama of some late versions of 1955 in hookah version

(click to enlarge the photos)

Let's look at the special cases now.


It is necessary to put oneself in the context of the time, we are at the beginning of the scuba diving and there is not yet a standard like today, everything is to be put in place.

GC45s were often modified according to the experience of its owner.

They could undergo transformations in order to fix it, improve its performance or simply customize it.

It must also be understood that pioneering divers, often former military members, were very proudly attached to the serial number of their regulator.

The latter symbolized their hierarchy in the seniority of the divers.

It is probably by this tradition that the Spirotechnique has long put forward on its regulators their serial number prominently on a manufacturer plate while the primary function of it is to allow after-sales follow-up.

This attachment to a small number of series and still relevant today in the world of collectors: for example a Mistral with address COGNACQ JAY has more sentimental value and market with a serial number with 2 or 3 digits that 'with 4 ... and yet they all date from the production year of 1955.


CG45 with standard bowl without manufacturer's plate.


The diving bottles at that time had no base and consequently they did not stand alone ... generating numerous falls and deformations of the bowls of the regulators, forcing their owner to make their change. The Spirotechnique sold for this purpose in its list of spare parts of the bowls ... but without the manufacturer's plate which was just installed on the bowl of the new regulator. This is the reason why we find quite a lot of CG45 whose pan of the wet chamber does not have a plate, or the 4 small holes of the rivets of a part plate. It is not a question of CG45 said military! Nor should they be confused with the archaic CG45s of 1946 that have their serial number engraved on the HP body. The problem with these GCs is that they are impossible to date precisely in the absence of the serial number.

Diaporama of the CG45 without label 

(click to enlarge the photos)

The archaic GC45 without manufacturer's label and without serial number stamped on the HP body.


These are simply old label regulators SARL!

Same as the regulators cited above, following the hazards of the dives the pan has to be changed.

I only know one copy exhibited at the Dumas museum in Sanary, it's mounted in hookah version (Photo 21).


The CG45 with large label SARL mounted in standard body and PRO configuration.


It is simply an upgrade version made by the owner of the time.

Indeed the particularity of the CG45 regulator is to be convertible and modular:

We can change the rear body and the archaic exhalation pipe against a standard PRO pipe without worry of adaptation!

This made it possible to adapt the regulator thus to a use with the constant volume PHOQUE.


GC45 serial number 516.


Finally, here is probably the most beautiful example showing the complexity of dating a certain CG45 regulator.

At first sight we are in the presence of a "small label SARL" with archaic bowl equipped with the rare and mythical FERNEZ mouthpiece ended of 1946. We can deduce that it dates from 1949 because its label is fixed vertically as " the big label" This is how I name the label that are mounted with the length parallel to the base of the exhalation pipe, in the manner of large label.

After 1949 all the small label SARL or SA found appear horizontal when one greaves the regulator on the block, forming an angle at 45 ° with respect to the base of the exhalation pipe.


By observing it more closely one realizes that its serial number is the 516, which is not logical in the chronology established previously.

Returning the regulator, we notice that the serial number has been stamped at the base of the HP body.

We are undoubtedly in front of a former CG45 without label of 1946, which explains the mouthpiece Fernez.

What happened to him ? I think that just his former owner wanted to put a label. Since the label is riveted and the serial number is punched "at the Spirotechnique" I think it is a particular request made for a personality of the diving community.

After reflection it is obvious that this modification dates from the beginning of the year 1949, at a time when the Spirotechnique had not yet chosen the positioning of the small manufacturer label on the body so that it is horizontal.


Diaporama of the CG45 N°516

(click to enlarge the photos)

Photo 21

Restauration of my CG-45 "standard version" 

with small label SA


Disassembling the regulator

Reassembling the regulator

Second restoration completed on March 8th, 2016 with the reception of the body part gone in rechroming on January 28th. My CG45 N ° 3783 is "as new". Ready for new adventures, like the Calypso soon, I hope with all my heart.

I present here the restoration of the CG45 N° 5002 of my friend Stéphane Eyme.

Good job done with passion.

I would like to thank the people who participated directly or indirectly in the development of this page. And more particularly Jacques Chabbert, Philippe Rousseau, Stéphane Eyme, Thierry Lafitte, Adair Ribeiro, Jean-Yves Tourbin and David L Dekker.

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