Description: Made of premium zinc-alloy material, Fit compatible for popular trailer couplings The Ball Lock is an anti-theft locking device that expands & locks inside the coupling of your trailer preventing the trailer from being connected to a Towball. Keeps vehicle and trailer connected; helps prevent theft of the hitch Covered key slot prevents dust and corrosion in the locking mechanism. Features: Type: Trailer Coupling Lock Color: silver Material: Zinc Alloy Size: 46*64mm PackageContents: 1 x coupling lock 50D 1 x hexagonal Allen Key 2 x safety Keys 1 x cylinder lock Installation instructions: Fig.1 : Insert the ball into the coupling claw. Remove the plug-in cylinder lock(turn the key in clockwise). Fig.2 : Insert the Allen supplied into the Allen socket - turning it to the right will spread out and fix the ball into place. Fig.3 : Insert the plug-in cylinder lock into the ball (turn the key clockwise). This acts to make the anti-theft protection fully operational. Dismounting is made to occur in reverse order.