- AL6061-T6 alloy seatpost clamp - Rounded edges and floating bolt/ovalized hole design protects carbon frames and seatposts - 28.6mm for 25.4mm seat post and steel frame - 29.8mm for 27.2mm seat post and chromoly frame - 31.8mm for 27.2mm seat post and aluminum frame - 34.9mm for 30.9mm seat post and aluminum frame, or 31.6mm seat post and carbon frame - 16mm height