Need help with an O-Ring ID...

[fox23]

Found this O-Ring in my bead blasting cabinet, and I have no idea where it came from. I took a quick look through some schematics but nothing popped out at me, hopefully one of the experts here can help. So far I've blasted lots of engine parts, forks, brake calipers and some other chassis odds and ends. Thanks in advance guys.

 

[fox23]

SOLVED! Old rocker cap o-ring. Must have still been stuck to the head when I blasted it.