The Lipo Fuel Gauge is the easiest way to see how much run time you have left on your Lipo batteries, whether you're in the air or on the ground. The simple color-coded LED lights show you instantly whether you can continue using your battery or if it's time to recharge. Over-discharging is one the most common ways Lipo batteries are damaged, so the Lipo Fuel Gauge is a key tool to ensure your batteries' longevity.