The Leofoto BPL-320 (320mm) and BPL-450 (450mm) Double Arca Profile Rail features a double Arca profile, which allows the user to position multiple mounting options at any position. The bottom profile allows the rail to be moved to any position in an Arca clamp to suit a variety of installed equipment. A large top-mounted spirit level allows quick and easy levelling of the rail for level panning and accurate measurements.