Ergon ST Core Evo Mens Saddle - MD/LG Black/GrayErgon ST Core Evo Mens Saddle MD LG Black Gray. Ergon ST Core Evo saddle features an ergonomicaly shaped relief channel to provide comfort over long distances. Twin shell with BASF Infinergy core sandwiched between isolates the rider from the road surface. The Ergonomic core dynamically adapts to pelvic motion providing a floating ride sensation. Gender specific relief zones accommodate the unique anatomical differences between men and women cyclists