For ease of use, the Sport Rider SE4 hitch bike rack comes out of the box set up as a 2-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 the patented "No Wobble-No Tools" hitch tightening system and includes locking frame hooks, a keyed-alike locking hitch pin, and an 8' security cable. This rack can fold flat against the car when not in use and tilts down for easy cargo door access. For 2" hitches only.