It a universal mount for attaching the accessory like monitor, light, audio recorder and more to the cage, plate that feature 1/4"-20 & 3/8"-16 threaded holes. The arm components are interchangeable,1/4"-20 & 3/8"-16 knobs on both ends are for quick and easy locking and release. It could be adjusted in different positions and angels by loosening and tightening the locking button.