SEAT POST Material: Steel / Die-casting alloy / alloy Diameter: Φ25.4 Φ25.6 Φ26.6 Φ26.8 Φ27.2 Φ28.6 Φ30.9 Φ31.6 Off set: 17.5 Length: 200 230 250 300 350 400 Finish: BED / Lathe an bk