Stainless steel lock body & shackle will not rust and is extremely strong. Weather Tough Seal protects keyway and shaft from dirt and moisture. Precision 4 pin tumbler mechanism resists picking. Fits coupler latch widths up to 2-3/4". Shaft end ergonomically designed to aid installation. Limited lifetime warranty. This adjustable lock protects and guards against tow-away theft. The lock works when the trailer is either connected to the tow vehicle or when the trailer is unattached. The lock prevents the coupler latch from moving, therefore preventing either the coupler to be removed from the ball, or not allowing a ball to be placed into the coupler. Six locking positions from 9/16" to 2-3/4".