Designed for longer periods of sitting and steeper uphills that E-mountain biking may provide Rearward positioned and anatomically adapted pressure relief channel prevents discomfort and numbness Raised ramp at tail of saddle and wide front for maximum support when riding uphill SM EMountain Pro: Carbon composite shell with orthopedic Comfort Foam with OrthoCell inlays SM EMountain Sport: Nylon composite shell with orthopedic Comfort Foam with OrthoCell inlays Recommended sizing for sit bone width: S/M 912cm, M/L 12-16cm