Some carbon, steel, and titanium bikes are made with an integrated seatpost (ISP) design. These systems have an extension above the toptube that take the place of a seatpost and require a mount system that allows the rider to install a saddle. Hence, the Ritchey WCS Seat Mast Topper, a set-up developed for specific outside diameter round extended seattubes. Ritchey has offered this system in 3 sizes, and it is currently available for 30.25mm and 34.9mm round OD masts.

The seatpost comes with a standard 1-bolt clamp to fit all 7x7 rails and Ritchey does offer clamp kits for all other rail diameters/shapes. Please be sure to use the correct size for each saddle or you may experience slippage.