TP4056 Lithium Battery Charger Module with Battery Protection is a lithium battery charge controller with auto-cut-off, over-discharge, and overcurrent protection systems. Which prevents the battery from overloading and overcharging. Thus ensure your battery-life-time. This controller also comes with a “charging” and “full-charged” LED indication system. Red LED Indication: Charging Green LED Indication: Fully Charged Input Voltage: 4.5V – 5.5V Fully Charged Voltage: 4.2V Battery Over-discharge Protection Voltage: 2.5V Battery Overcurrent Protection: 3A Charging Precision: 1.5% Dimensions: 26mm x 17.5mm