RockShox Dropper Post External O-Ring for Inner SealHead Description: The RockShox Dropper Post External O-Ring for Inner SealHead help to ensure a tight seal for the seal head without excessive biding. If you have multiple Reverb dropper seatposts or if you like to regularly service your seatpost, this kit ensures you have the parts on hand when you need them. Features: Includes 10 separate external O-Rings for servicing the inner sealhead of a Reverb dropper seatpost Specifications: Compatibility: Reverb A2-B1 | Reverb Stealth A2-B1