Locking Wheel Clamp & Trailer Towball Coupling Lock | Anti-Theft Security AL-KOHeavy Duty Wheel Clamps, Locks & Anti Theft Security Devices AL KO EASY CLAMP AND COUPLING LOCK >>> Secure your trailer, boat trailer or caravan against theft with this heavy duty wheel clamp and coupling lock. Heavy Duty Wheel Clamps, Locks & Anti Theft Security Devices 47mm (1 7 8") The Universal Coupling Lock helps protect trailers & boat trailers from theft by making it impossible to hook up the ball coupler to a vehicle. Suitable for both braked