MightyMonitor is a dashboard widget for OS X 10.7 Leopard and OS X 10.6 Snow Leopard that shows you the battery status of Apple Bluetooth wireless devices, including the Magic Mouse, Magic Trackpad, and brushed aluminum wireless keyboard. The widget changes color to warn of low batteries – with a low status warning (yellow/orange) at less than 25% remaining, and alert (red) with less than 10% remaining.