The extremely lightweight S-Works Power saddle has a stiff, FACT carbon shell and rails, and is a high-performance saddle that&';s designed to help you perform at your best. Its Body Geometry design, with our lightest level of padding, caters to both men and women, and helps deliver superior performance in all seating positions. Proven through blood flow testing and pressure mapping, the extra wide and elongated Body Geometry channel and proper sit bone support provides all day comfort. Patented Body Geometry design is lab-tested for both men and women to assure blood flow to sensitive arteries. Stiff FACT carbon fiber shell is tuned for support and ride compliance. Super-light PU padding for comfort and support on longer rides. Ultra-light oversized FACT carbon rails. Tough, lightweight, and water-resistant cover. Level 1 padding: Lightest level of padding for the most direct connection to the bike. SWAT(TM)-compatible mounts molded into the saddle base allow for sleek and integrated storage solutions. NOTE: Oversized 7x9mm carbon rails are not compatible with seatposts equipped with side-load clamp mechanisms for 7mm round rails. Size 143mm / Weight 159g Size 155mm / Weight 161g