This is an optional accessory that screws onto either the RLACS260 or RLACS233 and allows for secure mounting of an HD2 camera. It is of aluminum construction with a rubber liner to protect the camera.
The clamp is tightened with two M3 hex-socket screws that require a 2.5 mm allen key. It's is exactly the right diameter so that you cannot crack the camera even if fully tightened. This clamp is only suitable for HD2 cameras.