Reese UTL100 Universal Trailer Tongue Lock - Helps Prevent Theft Fulton Gorilla trailer lock helps prevent tow-away trailer theft with this easy-to-install coupler lock. Advanced locking mechanism discourages picking and prying. Fits all 1 7/8in., 2 and 2 5/16in. couplers. Heavy-duty, rust- and corrosion-resistant cast body. Includes 2 keys.