The WAR-LOK Cargo Trailer Lock is designed to fit most standard cargo trailer door latches. The lock hasp must be in good operating condition and not be excessively bent or deformed. The Trailer Lock should be installed on the right door on double rear doors. It may be installed on either latch on ramp doors. The lock may be installed on any side doors. To install the lock: 1. Place the WAR-LOK Cargo Trailer Lock over the hasp latch assembly. 2. Use the key to pull the lock cylinder down to release the lock. The WAR-LOK Cargo Trailer Lock is made from corrosion resistant materials. To insure years of trouble free use, it is recommended that the lock be lubricated periodically. To lubricate the lock, apply a few drops of light oil or spray lubricant directly into the key slot. Open and close the lock several times to work the lubricant into the lock mechanism.