Allows use of Bike Friday trailers with most standard bicycles. This hitch is heavier than the standard axle hitch and typically is used with the heavy duty Bike Friday trailer system. This hitch mounts on the QR rear axle for use with any standard bike. This hitch is included with the purchase of a heavy duty Bike Friday trailer.Please note: Any bike using disc brakes will need to have the hitch modified in order for there to be proper clearance for the disc. Please call with any questions you may have about this. Our phone numbers are 541-687-0487 domestic/800-777-0258 international.