Best used for vehicles, trailers, and RV hitch locks Trailer hitch lock is easy to install and remove Trailer coupler resists rust and corrosion; Advanced locking mechanism resists picking and prying Fits most 1-7/8 in. (48 mm), 2 in. (51 mm) and 2-5/16 in. (59 mm) couplers: Reese, Fulton, Valley, Atwood, Shelby, Putnam, Hammerblow, Dutton Lainson, UFP Includes one coupler lock, two keys