1. carbon bike seat post 2. super light carbon seat post 3. fashion design 4. model: ... -P4 Model:SP-P4Brand:TopmostMaterial:Carbon fiberFinish:3K,12K, UDDiameter: Ø27.2, 30.9,31.6,34.9mmLength:300,350, 400mmWeight:UD ... : Contact Person: Emily Lin Tel: 86-189-6584-0856Skype: emilylin0725 27.2 & 31.6mm mountain bike carbon seat post