Gegsite

4x2mm (innner diameter x thickness) But as I tried a few (black silicone, red special from SKF) all will inflated by CO2. (and no, there were no oil at all) So the one, what you get for it, is something special, milky-semi transparent kind o-ring. p.s.: I did ordered spare valves from tiger111hk and will test tomorrow

Spare from WELL ? Hey... I can NOT find a freakin o-ring for the CO2 magazine they have... HELP ME!

I've got a problem with the O-rings in my WELL CO2 AK magazine. The original is semi-transparent milky color (probably some kind of silicone) that is not so good at sealing. I bought and ordered some SKF black and some other silicone dark red color ones. Both are cr@p as they size is became bigger when the CO2 is probably diffuse into them. After I take out from the mag it is clearly bigger that is should. A few hours later they go back to the normal size.... I really want to solve my mag problem, as they have really bad output valve's. Sadly neither WE or other brands is compatible to it