Quick Guide to O-Ring Sizing (cylinder valves & Din)

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Hi Folks,

I keep getting asked what size O-ring is for such an such regulator and will this fit so and so etc etc...

What they really mean of cause is "which size O-Ring will fit my cylinder valve?".

There is a quick an easy way to size your O-Ring for your cylinder valve or Din fitting???    

                                                             Take this 'O-Ring'

to measure this O-Ring take a ruler and measure across the gap in the middle from the inner wall to the oposite inner wall                             

(<--?-->) like this


This will give you a figure x?

Standard dive cylinder O-Rings come in two sizes BS111 and BS112

these are 10mm(BS111) and 12mm(BS112) respectively.

This is a rough guide so you can quickly measure which O-Ring you require.

Dive cylinder O-Rings are standardised to the valves and din fittings and only come in the two sizes.


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