Product Description With the Seatpost Upper Piston Assembly for Reverb AXS B1 – 30.9/31.6 mm, you can properly service or repair your Reverb AXS. Ideal if your dropper post no longer holds pressure. Product Specifications: Application:MTB, Road, City & Touring Product Features: Original RockShox spare part compatible with RockShox Reverb AXS B1 for 30.9 and 31.6 mm diameters. Manufacturer Number: universal | 100 mm: 11.6818.063.000 universal | 125 mm: 11.6818.063.001 universal | 150 mm: 11.6818.063.002 universal | 175 mm: 11.6818.063.003 universal | 200 mm: 11.6818.063.004 universal | 225 mm: 11.6818.063.005 Contents: 1 x Piston assembly with shaft RockShox for Reverb AXS B1 Manufacturer: SRAM LLC 1000 W. Fulton Market 4th Floor Chicago IL 60607 USA info@sram.com Distributor: SRAM Europe Sales and Services B.V. Paasbosweg 16 3862 ZS Nijkerk Netherlands info@sram.com