This lock is for carrier to receiver security. Well show you how it assembles first, then well show you the lock applied to a bicycle rack. Before we can install the lock, there is a little bit of assembly required. First you have to open the hatch so we can the core, then you take off the back plug, and then we take our core and put our pass key in. After the core is secure, test the lock with the other set of keys. Now well try it on the pin. Since we have a bike rack installed on our two inch receiver, well show you how this works. Basically theres a lock washer that goes on first, then the flat washer. This is just like a regular nut and bolt assembly. Go ahead and install it to your bicycle rack. The kit provides you with a tool to snug it down with. Then we install the lock on the other side. There you have it, even if they unthread the bolt, they still have to get through the lock and they can not get the rack off. There you have it for part # STL2, the snug tite lock from Thule.