The Atlas CAL Bipod - with ADM-170-S mounts directly to any 1913 style Picatinny rail via the included ADM-170-S Lever. It was developed for shooters that do not desire the Panning feature of the V8 or PSR series of Atlas bipods. The BT65-LW17 has the larger Inner legs, patented 5 leg positions that do not rotate found on the Atlas PSR series.