A clamp is provided that allows for easily and securely mounting an object such as a PV panel to a rail having an internal recess or channel. The clamp utilizes one or more splice bars that extend into a recess of a rail that supports a PV panel. In one arrangement, the splice bar is inserted through an end of the rail into the recess such that a portion the splice bar extends beyond the end of the rail. A sliding clamp body engages lateral edges of the slice bar to, in one embodiment, compress a PV panel against a surface of the rail. The sliding clamp body may be affixed to the splice bar to secure the panel.