SQlab 621 M-D Active 2.1 CrMo Rail 240* Saddle BlkMaximum relief of sensitive areas. Offers optimal pressure distribution according to medical criteria for city bikes with a slightly forward bend to very upright riding position SQlab active system the saddle follows the pedaling motion, the comfort increases, the intervertebral discs are mobilized and the pressure on the sit bones minimized M D stands for maximized dip and, in combination with the high classic step shape, distributes the body weight