Caravan Security Products. Caravan Security Products, essential piece of caravan equipment is the Wheel clamps and Hitch Locks A good range of caravan Hitch Locks and Wheel Clamps for all Caravans Purpleline security products Sold Secure Approved Products Excalibur Wheel Lock, Centurian QF Wheel Clamp, Nemesis Wheel Clamp, Single Axle, Purpleline Full Stop Saracen Hitchlock.