The AD-VTA Vortex Tripod Adapter Kit is designed to adapt to ADM's 170-S Picatinny Mount or ARCA Mount directly to the head of the Vortex Rifle Tripods. This mount is only available with a standard lever. The ARCA version features a special short throw lever design which allows it to be loosened enough to slide to any position on the ARCA Rail while still retaining the mount to the rail. Designed to fit 38mm ARCA rails, but is adjustable to fit larger widths such as 40mm also. Features The AD-VTA Vortex Tripod Adapter Kit features the Patented QD Auto Lock™ Lever system which has the following advantages: Does not require proprietary tools for adjustment. Can be adjusted with your finger or a flat blade screwdriver. Lever can be configured to lock to the front or the rear. Superior clamping surface to ensure maximum rail engagement. American Defense Manufacturing ADM AD-VTA Vortex Tripod Adapter Kit w/AD-170-S QD Picatinny Mount AD-VTA-BLK-PIC in Black