The Ergon Digital Sit-Bone Measurement System lets your customer accurately determine their personal sit bone width. Simply sit on the seat and the LED readout will display their sit bone width measurement (cm and in). Match that number to any brand's saddle (that uses width based sizing) and your customer gets a saddle that perfectly fits their anatomy. Features: Scans the pressure created by the ischial tuberosity (sit bones) and calculates the width with millimeter precision.