Ergonomic MTB comfort saddle designed specifically around the male pelvis Rearward positioned pressure relief channel prevents discomfort and numbness Thicker and softer padding than SM models SMC Sport Gel: Nylon composite shell with orthopedic comfort foam with gel inserts for optimum pressure relief SMC: Nylon composite shell with orthopedic comfort foam padding Recommended sizing for sit bone width: S/M 912cm, M/L 12-16cm