100 Polyurethane Tank O-Rings (90 Durometer) [RED]
These are high quality, polyurethane tank o-rings for use with paintball CO2, HPA/Nitro tanks.  Polyurethane as a material is much more abrasion resistant than black buna-nitrile which is often sold as tank o-rings.  Buna o-rings nick and tear when screwed into your marker's ASA, causing leaks from the tank.  Polyurethane lessens the need to replace this o-ring.  90 durometer polyurethane is the most abrasion resistant o-ring material used in paintball.