Simple to use Lipoly low voltage alarm that is small and light for on board use. This plugs into the balance lead for detecting low voltage on individual cells. A loud alarm will sound and the LED will change from Green to Red if any individual cell drops to 3.3v or below. Spec. Lipoly Range: 2s~3s Size: 38x20x10mm Weight: 5g Voltage Accuracy: 0.03v Low Voltage Alarm Threshold: 3.3v (per cell)