Ritchey 1-Bolt Seatpost Clamps. Features: Optional 1-Bolt saddle rail clamps to replace stock clamps on Superlogic/WCS Carbon or WCS Alloy 1-Bolt seatposts with 7x9.6mm (Fizik carbon rail) or 8x8.5mm (most other carbon rail) clamps. Stock clamps fit standard 7x7mm rails Stamped code: DC for carbon/9.6, VF for carbon/8.5, F for alloy/9.6, S for alloy/8.5 Silver alloy clamps fit carbon seatposts, black alloy clamps fit alloy seatposts Note: alloy clamps work on the Wilier Cento series frames