SmallRig NATO Rail with ARRI Locating Screw 35mm BUN2501 attaches to ARRI-standard accessory mounts using a 3/8”-16 screw and two locating pins. It features a NATO rail on the top, compatible with NATO accessories like SmallRig NATO Ball Head Arm 2071, SmallRig NATO Clamp 1973 or 2207, making it easy and quick to release devices. The spring-loaded safety pins on both ends prevent your devices from accidentally sliding off.