Chronology and Typology


CG-45 regulators

CG-45 regulator, marketed from 1946 to 1955

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

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

To launch its marketing, Air Liquide will create a subsidiary: SARL La Spirotechnique which will be launched on May 26, 1946.


It was not until 1955 at the exit from the Mistral that the regulator was considered to be separable from the rest of the scuba unit. Divers will name it CG45 (abbreviation of 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 hookah version.

Indeed, the CG45 is the only double hose regulator of the brand which is convertible into hookah and vice versa. It suffices to remove the mechanism of the first stage by locking it with a plug provided for this purpose on the membrane side and then replacing the stirrup with a low pressure connection or the hookah pipe can be connected.


The typology and chronology of CG45.


I divided the CG45 into 2 types:

  • The CG45 with an archaic body (1946 - 1950) which is the rarest.

  • The CG45 with standard body (1949 -1955) which is the most common.

The CG45 with an archaic body


The CG45 with archaic body can be recognized by their fine tubing with a diameter of 22 mm and more particularly by that of expiration which is bent at 45 ° ( click on photo 2 ).

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

This configuration will be quickly abandoned to bring the regulator between the diver and the bottle in order to protect it, no longer requiring to bend the exhalation tubing.

Photo 1
Photo 2
Photo 3

Archaic models come in 3 versions:

  • The without manufacturer's label

  • Large SARL label

  • Small SARL label


They are distributed chronologically as follows:

The first CG45 without manufacturer's label.


At first (in 1946) the serial number was stamped directly on the exhalation bowl ( Photo 4 ) and then on the back on the HP body ( Photo 5 ) just next to the yoke, the regulators of this period dates from 1947 until begining of 1948.

I only know 3 units: the serial number 150, 516 and 568. This variant is therefore very rare. These first regulators were sold with a FERNEZ metal mouthpiece for the very first of 1946 and 1947. In photo 6 , the picture presenting the regulator in the 1946 catalog.

Photo 4
Photo 5
Photo 6
Porfolio of N ° 568

The big SARL manufacturer's label


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

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

This assumption is based on the fact that I found N ° 537 ( click on photo 7 ) with label and N ° 568 without label but with the serial number stamped on the HP body.


The CG45 with large SARL label is marketed with a large rubber tip produced by GODEL for La Spirotechnique ( Photo 8 ).

Note that the serial number 864 ends with the letter N. It is mounted in hookah therefore can be N for Narguilé who mean hookah in french ....

( Photo 9 and 10 )

This regulator would come from the arsenal of the Orient. We do not know the reason for the presence of this letter, however even if to date it is the only large SARL label known with this feature we can assume that a small series has been marketed.

The biggest serial number of a CG45 large SARL label known to date is N ° 1097 which means that a quantity of about 550/600 units was produced however my research allowed me to find only 9 units all around the world, making it one of the rarest and most sought-after regulators by collectors. In photo 11 , the image presenting the regulator in the 1948 catalog.

Mistral 005 copie.jpg
Photo 7
Photo 8
Photo 9
Photo 10
Photo 11
Mistral 007 copie
CG45 N°1097
Mistral 005 copie.jpg
cg45-grande plaque.jpg

You will find in slideshow the 10 large labels of private collections that I have found to date around the world: the numbers 537 - 631 - 684 - 763 - 835 - 864N - 941 - 970 - 1080 -1097 ( click to enlarge the photos)

The small manufacturer's label SARL


In 1949, the CG45 with small SARLlabel appeared, it came in 2 variants:


-The one with the archaic body which is still produced but the GODEL rubber mouthpiece is replaced by a straight metal mouthpiece as the Fernez type ( Photo 11 ).


-The one with the first standard body( Photo 12 ) with a configuration called PRO (professional). It has been specially developed for the brand new constant volume (drysuit) developed by Spirotechnique: the PHOQUE suit ( Photo 13 ).

On this body the tubes have a larger diameter since we go from 22 to 25mm knowing that the expiration is no longer curved. They have threaded connections welded with tin which not only allow to equip the regulator with the famous PRO tip but also to easily dissociate the hoses at the body of the regulator or the mouthpiece which remains attached to the hood .

As of today, the smallest serial number of a known CG45 small label SARL is No. 1137 and the largest No. 1871 , an estimated production of around 750 to 800 units. Despite this I have managed to identify to date only twenty units around the world.

An important detail, the first small labels SARL units were mounted "as a large label",I means vertically, the length of the label perpendicular to the pipes ( Photo 14 ). It was probably only from 1950 (around the serial number 1200) that the labels were fixed horizontally ( Photo 12 ). In photo 15 , the image presenting the regulator in the catalog of 1950.

There are also 2 special cases found to date, the number 516 which I am talking about below and the 583 (Photo 16) . It should be understood that today we are working on hypotheses based on observations because unfortunately the archives of La spirotechnique were destroyed during the move from Levallois to Carros and that all the pioneers of spiro died today.

It would seem that in the years 1949/50, (for me the most probable hypothesis), the La Spirotechnique sold in spare part of the pans assembled with small SARL label by stamping the serial number at the request of its owner. But very quickly this practice would have been abandoned (since 1951) by selling a virgin pan, without label, less restrictive for the after-sales service.

Photo 11
CG45 petite plaque SARL
Photo 14
Photo 12
Photo 15
Photo 13
CG45 petite plaque SARL 001.JPG
Photo 16

Slideshow of some CG45 small SARL labels found in various collections

(click to enlarge the photos) .

The small SA manufacturer's label


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

Appearing a new small manufacturer's label with the mention SA LA SPIROTECHNIQUE.

The manufacture of the archaic body is abandoned in favor of a new variant in parallel with the standard PRO version, which I called the standard version ( Photo 17 and 18 ).

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

To date, I have found CG45 with small SA plate included between serial number N ° 1960 to N ° 6194.

Photo 17
Photo 18
CG45-plaque 5127.jpg

Slideshow of some CG45 in SA label version

(click to enlarge the photos)

These CG45 are divided into 2 groups:


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

There are mostly regulators mounted in yoke versions because the hookah 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 significance is unknown at this time, but probably a series for the Navy. ( Photo 19 )


  • Another variant with at least 62 units of regulators will be produced in 1953 with the label known as “mounted upside down” ( Photo 20) (from serial number 4166 to 4228 with certainty) This designation comes from the fact that if we rigged the CG45 normally (pipes oriented upwards) the label appears upside down. This is not a factory assembly error as I read on some discussion forums. This series is designed to be rigged down the tubing to increase the protection of the rubber hoses (Maybe for use in caving). Of course by respecting this configuration the label will appear in a correct position. This assembly will even be taken up later by the Spanish manufacturer Nemrod on the black label Snark III regulator ( Photo 21 ).

Photo 19
Photo 20
Photo 21
  • The second group of CG45 with SA label is a last series produced in 1955. It probably consists of 1000 units comprising exclusively CG45 in hookah having the distinction of having a low pressure elbow connection, 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 hypothesis is based on my observations made in private collections and museums, 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 is around 6,200 units ... How many are left? Difficult to say but as I found 72 currently in private collections after a good ten years of research I think that by being optimistic there should not remain more than 200/250 units around the world.


Slideshow of some late 1955 versions in hookah version

(click to enlarge the photos)

Let's take a look at the special cases now.



We must put ourselves in the context of the time, we are in the beginning of scuba diving and there is no standard yet like today, everything is to be put in place.

The CG45 often underwent modifications according to the experience of its owner.

They could undergo transformations in order to repair it, improve its performance or simply to personalize it.

It should also be understood that the pioneer divers, often made up of former soldiers, 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 through this tradition that Spirotechnique has long put forward its serial number on its regulators, as shown on a manufacturer's plate, while its primary function is to enable after-sales monitoring.

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


CG45 with standard bowl without manufacturer's label


The diving tanks at that time had no base and consequently they did not stand alone… causing numerous falls and deformations of the regulator bowls, obliging their owner to change them.

Spirotechnique sold for this purpose in its list of spare parts for 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 a lot of CG45 whose pan of the humid chamber has neither label, nor the 4 small holes of the rivets of a part label.

It is by no means a CG45 called military! They should also not be confused with the archaic CG45 of 1946 which have their serial number engraved on the HP body.

The problem with these CG45 is that they are impossible to date precisely in the absence of the serial number.

CG45sans numero.png

Slide show of a CG45 without label

(click to enlarge the photos)

The archaic CG45 without manufacturer's label and without serial number stamped on the HP body.


They are simply former SARL label regulators!

Same as the case mentioned above, following the vagaries of the dives the pan had to be changed.

I only know one copy exhibited at the Dumas museum in Sanary, it is mounted in a hookah ( Photo 22 ).


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


It is simply an upgrade made by the owner at the time.

In fact, the particularity of the CG45 regulator is that it is convertible and modular:

You can change the rear bowl and the archaic exhalation nozzle against a standard PRO nozzle without worrying about adaptation!

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


The CG45 serial number 516.


Finally, here is probably the most beautiful example showing the complexity to date certain CG45 regulator.

At first glance we are in the presence of a "small SARL label" with an archaic bowl fitted with the rare and mythical FERNEZ mouthpiece from 1946. We can deduce that it dates from 1949 because its plate is fixed vertically "to the big label" , this is how I name the plates which are mounted with the length parallel to the base of the exhalation nozzle, in the manner of large SARL plates.

After 1949 all the small SARL or SA labels found appear horizontal when the regulator is rigged on the block, forming an angle at 45 ° relative to the base of the expiration nozzle.


By observing it more carefully we see that its serial number is 516, which is not logical in the chronology established previously.

Returning the regulator we see that the serial number has been stamped on the base of the HP body.

We are undoubtedly in front of an old CG45 without label  from 1946, hence the Fernez mouthpiece.

What happened to him ? I think that simply its former owner wanted to put a manufacturer label on it. Since the plate is riveted and the serial number is stamped "Spirotechnique"

Upon reflection it is obvious that this modification dates from the beginning of 1949, because probably for a short period Spirotechnique supplied as a spare part the front bowl with a small SARL label by stamping the serial number of the regulator.



Photo 22

Slideshow of CG45 N ° 516

  (click to enlarge the photos)

Photo 22

Restoration of my CG-45 "standard version"

with small SA label

N ° 3783

gamelle avant démontage
démontage des colliers
démontage du bec de canard
démontage de la gamelle
gamelle avant+membrane
gamelle arrière + corps HP
démontage complet
démontage du 1er étage
démontage complet du 1er étage

Disassembly of the block

gamelle nettoyée
pièces caoutchouc lavées et talquées
remontage coté membrane
mise en place ressort MP
remontage écrou-chapeau MP
remontage 1er étage
assemblage bloc HP/étrier
gamelle avant assemblage
gamelle remontée

Reassembly of the block

plaque constructeur N°3783
Rivets en cuivre à martellés
plaque constructeur
bec de canard
bec de canard
Gamelle avant
remontage de la gamelle complète
nettoyage du chrome
remontage des tuyaux annelés
CG45 N°3783

Second restoration completed on March 8, 2016 with the reception of the bowl part in rechromage on January 28. My CG 45 N ° 3783 has a new look. Ready for new adventures, a bit like the Calypso soon, I hope with all my heart.


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

Good job done with passion.

Description of how the CG-45 works


CG-45 block diagram

This regulator allows the supply of sufficient air, which is automatically relaxed in the lungs of the diver.

Its dorsal position ensures maximum respiratory comfort, the membrane being at the level of the bronchi.

It consists of two relaxation floors. The first stage transforms the high pressure into an intermediate pressure (so-called medium pressure) of around 11.5 bars. The second stage supplies on demand air at prevailing ambient pressure at any depth.

Its ease of use effectively eliminates the risk of shortness of breath.

Its design cannot cause a lack of air, its circuit open to expiration, leads bubbles out of the field of vision.

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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