Cannondale KNOT SystemSix Aero Seat Binder K26139The Cannondale KNOT SystemSix Aero Seat Binder K26139 has what you need to replace Original Cannondale 2019 generation SystemSix aero seat binder kit. Includes all the hardware including modified kit for 47cm frames. Cannondale recommends regular maintenance for a long, trouble-free life.884603746837