Our Head-Lock bolts onto the bottom of the head and stays on the camera head through mounting changes. You securely lock and unlock the camera head to the Mitchell mount in seconds without a separate tie-down. The locking unit passes through the center of the Mitchell mount. Turning the knob extends 3 angled jaws that lock the head in place. Does not fit some Arri Gear Heads. See also OCHL specifically made for Oconnor heads.