Trailer coupler lock
Choosing a trailer coupler lock is about securing the connection point where a trailer attaches to the tow vehicle. A coupler latch lock blocks the release handle so the hitch cannot be unlatched while parked. Shoppers comparing a trailer coupler latch lock often also look at a trailer coupler and hitch pin lock set to cover two separate vulnerabilities: the ball socket up front and the receiver pin at the rear. The right choice depends on coupler style, how the trailer is stored, and the level of mechanical deterrent you want.
The direct answer
A trailer coupler latch lock answers the immediate need of preventing someone from lifting the coupler latch and dropping the trailer onto a different ball. The lock fits around or through the latch lever so the mechanism cannot move far enough to release. This turns the coupler into a fixed anchor point that resists casual theft. The critical condition is fit: some locks suit a straight latch, while others work better with a wrap-around yoke or a trigger-style lever, so the coupler design determines whether a lock can close cleanly.
For broader protection, a trailer coupler and hitch pin lock set addresses both the trailer side and the tow vehicle side. The coupler lock blocks the latch, while the hitch pin lock replaces a standard receiver pin with a locking version. That pairing is useful because a trailer can be stolen by opening the coupler or by pulling the ball mount from the receiver and installing the whole assembly on another vehicle. Matching both points improves access control without requiring a single lock to do two different jobs.