The Box One Disc Brake Adapter is designed to improve braking control on frames where disc brakes were not standard. Compatible with 2 types of dropouts and 3-10mm hubs, the Box Disc Brake Adapter goes over your hub's axle and mates with the frame's dropout in the right configurations allowing mounting of a standard post mount disc brake caliper. Please note this product is NOT universally compatible. We strongly recommend reading the Compatibility and Installation instructions for details before purchasing. FEATURES - 3-10mm hub - 6061-T6 aluminum - 140mm Brake Rotor Only - Post Mount Caliper Compatibility - 150lb Rider Weight Limit