For use on 1, 2, 3 and 4 axle trailers equipped with electric brakes. These complete systems incorporate the highest quality components in trailer breakaway systems. Meet or exceed Department of Transportation (DOT) specifications regarding trailer breakaway and holding requirements. If a breakaway occurs between your tow vehicle and your trailer, the breakaway systems will automatically apply consistent braking power to your trailer brakes. Quick and easy to install, the systems come with a weather/corrosion resistant, heavy-duty polymer case to protect the battery and charger.