Does anyone have the specification for the O-ring that fits in the face of an older-style cylinder valve (A-Clamp). I know the size is 111 but what shore number should I buy? T'internet seems to suggest 70 which are available. I can get 100 nitrile o-rings of unknown hardness for £10, Viton ones of known hardness cost a bit more but in the big scheme of things are still cheap so I would like to buy the correct thing.
Every time I buy a big box of O-rings its the size that gets used up first - almost always by buddies!