The Area 419 ARCALOCK Clamp, Barricade Kit includes the ARCALOCK Clamp and Barricade stop. The kit can be used independently as a barricade stop, or paired with an Atlas bipod (not included). The ACRALock clamp utilizes a proprietary two-stage screw design. The clamping screw features two different thread pitches. The coarse 16tpi is used when no tension is on clamp, allowing rapid movement of the clamp vs others on the market. With high speed comes low torque though, so to counteract this as soon as the clamp sees tension it will switch to the 32tpi threads in the knob to give you extra torque when not using on an ARCALOCK rail. Approximately 1/4 Turn releases the clamp from the detents on the ARCALOCK rail for movement, one full turn releases clamp to be removed from rail. Pro tip: If you're looking to convert a Picatinny bipod to Arca, such as the Atlas BT-10, you'll also want to add the Area 419 Picatinny Adapter (Part# 758480) to your cart. FeaturesClamp directly bolts to Atl...