O-ring size for Evanix RS1 rear air tube at gauge block please

Hi guys,

  I need my Altaros rebuilt. Until then I want to take it out & put the back O-ring in, try the rifle at full power with heavy .22's.

No One I know sells rebuild kits. I know who'll reseal it and set it up optimally. I don't have money right now for any of that. One O-ring is holding me back. Can I get the exact size & durometer please?

Also, I e-mailed Altaros. I inquired about a rebuild kit for my reg. I don't see anywhere on their sight where they seal just reseal kits. I know the reg comes with a kit but I bought this 2nd hand. O-ring was already out for it to equalize & breath, & no reseal kit.

Thanks in advance for any info fellas. If anyone happens to be able to just put a kit together for me, I'd gladly pay your asking fee as I can install it all myself & set reg to same height as Starrett depth gauge reads before I rebuild. That should get me close, as I have no crhony or reg tester.