The Bump-It is used in conjunction with Lipperts Jack-It. The Bump-It is inserted into the tow vehicles hitch receiver. The upper section of the Jack-It is removed from the trailer and mounted onto the Bump-It. This allows you to switch your bikes between your tow vehicle and travel trailer. Manual included. Used only once and it worked great (then we bought a motorhome). It will fit 1-1/4 and 2" receivers. Cash only sale.