Ergon SMC Core Men's Saddle - SM/MD, Black/GrayErgon SMC Core Saddle The patented Core design allows the saddle to effortlessly follow pelvic movements enormously reducing pressure on the sit bones and genital area. The floating TwinShell concept with the ergonomic core supports the natural pelvic movements while pedaling, actively relieves the sit bones, and reliably dampens bumps caused by the riding surface. S M fit sit bone width of 9 12cm, M L fits 12 16cm Saddle shell made of Nylon Composite