Locking your trailer coupler is the best way to keep your trailer safe. A coupler lock protects your trailer by making it nearly impossible for a thief to hook up your trailer to their vehicle. The Fastway FORTRESS keeps your trailer secure. It is the toughest coupler lock available, made from the highest corrosion resistant material and fits virtually every coupler style. In fact, after years of testing, we haven’t found a coupler it doesn’t fit. The lock has a hinged cover, protecting it from dirt, debris, rust, water, and ice. With its thick housing, incredible strength, and a lock that’s almost impossible to pick, you can be confident your trailer is safe.