selle ITALIA Adult Novus Super Flow Saddle SuperFlow elongated cutout ensures maximum pressure relief and comfort Size Small = S3 rating in ID Match system means saddle is optimized for narrower-spaced sit bones and a high pelvic rotation capacity Size Large = L3 rating in ID Match system means saddle is optimized for wider-spaced sit bones and a high pelvic rotation capacity Titanium rails are lightweight and resilient Synthetic Fibra-Tek cover balances softness and durability