How to determine O-ring size

[Subculture]

You can purchase o-rings in metric dimensions in the UK and Europe. You may also be able to purchase metric o-rings from Canada, they're a little more comfortable with the metric system over there (that should **** off Dave).

I use these guys-

http://www.polymax.co.uk

Good company to deal with, they also do lots of rubber goodies for subs like flat rubber sheet, hosing etc.

Andy