Captain O-Ring LLC Smart Parts Shocker SFT/NXT - 3x Oring Rebuild Kit Contains all o-rings needed for three standard rebuilds of your marker Contains o-rings for your marker's firing assembly (bolt), high pressure regulator, LPR (if applicable), etc Also available in Captain O-Ring Color Coded O-Ring Kit: http://amzn.com/B00FDZF78C Includes o-ring placement list as well as a real-size o-ring size chart to quickly match o-ring sizes All of our buna o-rings exceed ASTM standards. We are proud to offer the highest quality products in the industry