The TowSmart Boomerang Hitch Pin and Coupler Lock protects your boats, campers, trailers, equipment and other valuable assets from theft. It easily secures your ball mount or hitch accessories to the receiver hitch. Simply insert the pin into the fastener hole once you have positioned the ball mount or hitch accessory in the receiver hitch. The Boomerang Hitch Pin offers a patented, reversible dual diameter design that fits 1/2 in. and 5/8 in. receivers. It provides a tight and secure fit and is made of corrosion-resistant materials designed to withstand harsh weather conditions. The Coupler Lock secures the trailer to the ball mount when in tow and provides superior protection to the trailer when it is left unattended. Weather resistant dust caps protect the locking mechanism from moisture and dirt build up. This product is not recommended to remain on vehicles for an extended period of time. Includes 4 keys that are keyed alike for convenience rather than having multiple keys.