GoTow is happy to present our solution to some age old problems, accidental separation or theft of your trailers, with the Universal Coupler Lock. This easy-to-use lock simply blocks the area that the ball mount hitch would go, making it no longer possible for thieves to simply hook up and go. This lock is also designed to fit 1 7/8", 2", and 2 5/16" couplers, meaning almost any hitch can be locked down. With a heavy duty steel construction, it is perfect for everyday use or even for locking up in long term storage. This set also includes two keys, so you can always keep one in your car and another in a separate location for security. Order now and never worry about losing a trailer ever again! Ball diameter is 1.88". Set includes 2 keys. Overall dimensions are 5.43" x 2.69" x 5.50".