Trailer Hitch Locks
Apparently, some people like to steal trailers. It does not matter if it is a boat trailer, cargo trailer, or car trailer. The best option to prevent trailer theft is to install a trailer hitch lock. Another option is to use wheel boots and clamps on your trailer just like you would on a car.
Blaylock Industries - This company manufactures and sells a variety of different options to lock the hitch on your trailer.
DuraSafe - Offers a variety of products to protect your trailer.