Service kit to assist in scheduled maintenance and/or rebuild of RockShox dropper seatposts. Includes Blue 1-Piece U-Cup Seal Internal Floating Piston (IFP) Requires RockShox Specialty Tools to perform Service: Post Bleed Tool, Oil Height Tool, IFP Height Tool B1 posts have a black return speed adjuster on the remote and "ROCKSHOX" laser etched logos on stanchion by the saddle cradle Rebuilds IFP, Poppet, Seal Head, Dust Seal, Piston and Bushing