RockShox Main Piston Seal O-Ring Description: The RockShox Main Piston Seal O-Ring helps to ensure a tight seal on the main piston of a Reverb Dropper post and helps to minimize play in the actuation of the seatpost. If you have multiple Reverb dropper seatposts that need servicing or if you like to regularly service your seatpost, this kit ensures you will have the parts on hand when you need them. Features: Includes 10 separate main piston seal O-Rings for a Reverb dropper seatpost Specifications: Compatibility: Reverb A2-B1 | Reverb Stealth A2-B1