The Area 419 1913 Picatinny Adapter for Arca Clamps is a 4-slot section of rail that can be attached to an ARCALOCK Clamp, allowing its use with any Picatinny style bipod. For instance, this adapter is required to attach the Atlas BT10 2-Screw Picatinny model to one of the Area 419 Arca clamps. This rail also includes an integral flush cup sling attachment.