The Voltage Monitor is a sensitive, weatherproof, vibration proof three LED voltmeter that gives a clear indication of your battery’s condition with a quick glance. The Voltage Monitor lets you know if your system is low, normal or over-charged. If it drops to the “low” LED, or flickers between the “normal” and “low” LED, it indicates that your bike's battery voltage is slowly falling and that the alternator is not keeping up with the load. This is especially good information to monitor when riding a smaller bike, when higher-load accessories like electric vests are being used. (Most smaller machines have limited excess battery charging capacity...) The LEDs are housed in a small matchbook-sized, durable, easy-to-install case (included double stick adhesive) with epoxy incapsulated electronics. Hook up to any keyed-on power wire. Even more information when installed combination with the #4949 three LED ammeter. 1.5"×1"×.375.