A quick-release lens support by Kirk, to be used with the Nikon 200-500mm f/5.6E ED VR or Sony FE 70-200mm f/4 G OSS lenses. Its purpose is to stabilise lenses & reduce shifting when you loosen the lens collar to rotate the camera. It must be paired with the NC-200-500 lens collar with Nikon lenses & paired with the SRC-70-200-4 lens collar with Sony lenses.