The #13 angle bolt hardware is designed to be used on a bed rail that is 1.5" x 1.5" angle. The angle bolts come complete with custom cap nuts. When threaded onto the bolt the shank of the nut actually penetrates the guard rail leg itself thereby providing a flat surface, thus eliminating a hazard. The nut is put on using an Allan wrench, which prevents easy removal of the guard rail by a child.  This hardware is compatible with the following guard rails: LS-50, WS-76