BBB- dimensions given on the FX parts diagram for O rings are cross section size, then ID. Go to oringsandmore. Scroll to the metric buna70 section and pick out all the o rings required for this gun, as I did. There are I believe two o rings that are Buna90, so watch for those. I believe yours is an MK2? FX website has the parts diagram for you to download.
Regulator o rings for the MK2 with AMP regulator size is 23.3mm ID x 2.4mm thickness(cross section). I know, the commas instead of the periods thru me off, also.
The hydraulics store.com has dowty seals which you’ll need, as the wildcat has two of them, an M7 and an M12. The M12 is the one at the rear of the air tube, and depending how hard you re tighten your air tube back on(sheet metal workers grip, I know) you could easily cause that seal to leak. Mine was leaking just the other day, I found, from over tightening it to adjust the fill probe hole to my liking. Glad I had the spares.
Lastly, there are two o ring sizes not given- the o ring on the valve seat and the one on the valve stem. I’ll get that to you in a bit.
Total cost for o rings will be around $15, and you’ll have enough to re seal your entire gun 50 times, lol.
Or, if you wanna go the simple route and not have to pick o rings off of the parts diagram, Captain o rings has a pre put together kit with enough o rings to reseal your entire gun twice. I believe it’s around $35 for the kit, and you can download a location diagram as to where the o rings go on the gun. No dowty seals are included in their kit.