For ease of use, the Sport Rider SE4 bike hitch rack comes out of the box set up as a two bike base unit. The two bike add-on kit (included in the box) is easily assembled to the base unit by installing & tightening two bolts. Features patented "No Wobble-no tools" hitch tightening system, and a keyed alike locking hitch pin with 8' security cable is included. Folds flat against the car when not in use and tilts down for easy cargo door access. For 2" hitches only.