U.S.E. Ultimate Alien Carbon Seatpost 31.6 x 400mmUsing a larger (3mm hex key) single bolt central to the clamp design, the Alien Cyclops makes adjustment easier and faster Intelligent design and high grade materials ensure that the weight is as low as possible while maintaining durability and long lifespan TECH SPECS model Alien diameter 31. 6mm length 400mm setback 10mm weight 140g material carbon color 3K matte carbon