Ok so i looked at the bottom of the air tanks and here's what I found :
The manufacturer is indeed SM. GERZAT, and old french brand wich was sold to LUXFERS FRANCE.
I found this article on a french forum that explained what iain/hsm said.
Nouvelles recommandations de la SM Gerzat pour les bouteilles en aluminium - Forums plongée Plongeur.com
Here's the google translate link in english :
Google Traduction
So yes, there is indeed a big product recall since 2005 on thoose things. It could be funny because it's in use from many decades but they warn only in 2005 ...
I tried to contact the number of in the botton page to call LUXFER, it falls on a switchboard, tried all numbers but no answer, i'll try later in the day, they must be eating or sleeping at 1:30PM ..
BUT !!!
This is what is marked on my tanks :
SM. GERZAT N°
24317 . ---> I think this is the model, so its' not a 5000 range. But it could be even worth
don't know about this ..
0 à 15% ---> O2 ?
178 HPZ PS 200 HPZ ----> Searched on Google, this HPZ means "héctopièze", an old unit, similar to bars. 1hpz = 1 bar. So nominal pression is 178 bar and max is 200. Good to know.
11 - 2 - 1960 ----> Creation date. So it's definitevely not a 5000 range, they says in the article that they was built 25 years ago, not 60 years ago.
Well, I think that I have all technical specs. Now I have to search for reliability informations on this. Does anyone have any information on it ?