Ritchey wcs 1 bolt zero offset seatpostthe wcs 1 bolt zero offset seatpost features ritcheys unique sidebinder single bolt clamp design which provides quick and secure engagement also its wide saddle clamp plate reduces stress on lightweight hollow saddle rails this model also features a zero offset to suit those who prefer a slightly more upright riding position features material 3d forged tr741 aluminium shaft and clamp low profile head wide saddle clamp rail clamp size 7x7mm offset