Designed with our Retul fit specialists, doctors, and engineers, the Sitero is the best-fitting saddle for aerodynamic time trial positions. A wide channel, progressive shape, level 2 padding and multiple width options provide optimal comfort and support for long distance rides in an aerodynamic position. And to further ensure that this is the best Triathlon/Time Trial saddle on the market, it features hollow Chromoly rails and SWAT(TM) mounts that allow for aerodynamic storage of your ride essentials. Next-level comfort for riders of all sizes while in the aero position. Lightweight and supportive PU padding for comfort and support on longer rides. 4-way stretch cover material for unparalleled Pelvic rami comfort. Level 2 padding: Medium density foam for bike feel with additional cushioning. Durable hollow Cr-Mo rails. SWAT(TM)-compatible mounts molded into the saddle base allow for sleek and integrated storage solutions. Size 130mm / Weight 227g Size 155mm / Weight 245g