I've seen on the Arc website you can request O-rings, and found some limited information here, but what is the correct size O-ring I can purchase locally? Thank you!
I prefer and use Poron/silicone construction. Buna is almost as long lasting and much cheaper. Arc will send you a free o-ring and foam kit, if you request by email. I would just send a SASE with my request by snail mail,. imho
Fibonacci, both are excellent at sealing out water. I prefer the silicone ones. I find that they deform less,over time, from grit and sand than the Buna rings.