Trailer Brakes lock out Key for UFP Actuator Product Description: Manually lock out your trailer brakes so you can back up your trailer. Commonly used on steep driveways or if the vehicle is not wired correct for the 5th pin wire to disengage the brakes. Fits Behind the front Slide Pin CAUTION: DO NOT LEAVE KEY IN WHILE BOAT IS IN TOW. LEAVING THE KEY IN WILL LEAVE YOUR TRAILER WITH NO BRAKES!!