This Ritchey 1-bolt carbon seatpost clamp kit is a stock replacement kit for Ritchey 1-bolt Superlogic and WCS carbon seatposts. These kits come in different clamp slot diameters to accommodate the larger diameter carbon rails found on contemporary saddle designs. This clamp kit includes the main bolt, washer, one threaded and one un-threaded rail clamp. The central carrier that connects to the plates is not included. You can find those under the Complete Clampset designation. Make sure to choose the correct rail size for proper fitment to you saddle.