This stiff competitive road/tri saddle is contoured to position the rider for optimal power transfer & comfort; its extra-wide BG channel maximizes blood flow.> Patented Body Geometry design is lab tested to assure blood flow to sensitive arteries> Stiff carbon-reinforced shell tuned for ride compliance> Tuned-density PU foam padding is lightweight & supportive> Ultra-light & strong oversized FACT™ carbon rails> Tough light & water resistant Micromatrix cover> Size 130mm/ Weight 153g> Size 143mm/ Weight 160g> Size 155mm/ Weight 167g> NOTE: Oversized 7x 9mm carbon rails are not compatible with seatposts equipped with side-load clamp mechanisms for 7mm round rails