Give yourself peace of mind with the Koolatron 12 volt Battery Saver. When plugged into your vehicle's 12 volt outlet, the Koolatron 12 volt Battery Saver can sense if your vehicle voltage drops below 11 volts. The Battery Saver then shuts off the current to all 12 volt accessories in order to prevent further drainage. It will reconnect automatically when you start your vehicle. The 12 Volt Battery Saver gives you peace of mind by ensuring you will always be able to start your vehicle.