Attaches to a 35mm thick bed headboard. The prong on the model is needed to secure it to the headboard, in the empty space in the headboard. If yours doesn't have one, you can remove the prongAttaches to a 35mm thick bed headboard. The prong on the model is needed to secure it to the headboard, in the empty space in the headboard. If yours doesn't have one, you can remove the prong