Ergonomic Road saddle designed specifically around the female pelvis Forward positioned and anatomically adapted pressure relief channel prevents discomfort and numbness SR Pro Carbon: Carbon composite shell with orthopedic AirCell foam with OrthoCell pads SR Pro: Nylon composite shell with orthopedic AirCell foam with OrthoCell inlays SR Sport Gel: Nylon composite shell with orthopedic comfort foam with gel inserts for optimum pressure relief Recommended sizing for sit bone width: S/M 912cm, M/L 12-16cm