Master Lock offers a heavy-duty King Pin Lock for semi-tractor trailers and fifth wheel trailers. The device locks around the king pin of a trailer to stop thieves from driving away with your valuable cargo or RV. The Master Lock King Pin Lock is engineered to withstand physical attacks. Manufactured of a solid aluminum alloy, the lock only weighs 6.5 lbs., making it easy to transport. The integrated no. 5 padlock resists drill attacks and attempts to pull the cylinder from the lock.