Amazon.com: Aupar Heavy Duty Solid Steel Trailer Lock Fits 2 5/16-Inch Trailer Couplers, Anti-Theft Trailer Hitch Lock, Red : Automotive
TrailersPlus - Protect your investment with Interstate's Trailer Defender™ High-Security Coupler Lock. The most heavy-duty, dependable, and theft-proof coupler locks on the market! | Facebook
Reese Towpower 7088333 Trailer Coupler Lock Universal Fit Heavy Duty Chrome | eBay