Ritchey WCS Carbon 1-Bolt Seatpost: 31.6, 400mm, 0 Offset, BlackRitchey WCS Carbon One bolt. Head uses less aluminum than other designs, resulting in reduced weight. Product Details: 1 piece shaft and cradle support Design allows adjustments to be made with one easily accessed horizontal bolt Head uses less aluminum than other designs, resulting in reduced weight SideBinder clamp uses a single 5mm bolt to secure the saddle Wide saddle clamp reduces stress on lightweight saddle rails Works with all saddles with