5V 2A Charge and Discharge 3.7V 4.2V Lithium Battery Boost Module, when using a lithium battery, its charge, and discharge need circuit protection to protect the lithium battery from being charged or damaged or to obtain a safe power supply from the lithium battery. The module has four LED indicators to indicate the current power of the lithium battery.Features:Low-level trigger.Over-current, over-voltage, short circuit protection.The module comes with a lithium battery protection function.Specifications:Charge voltage: DC 4.5V-5.5V(Recommend DC 5V)Charging current: 0-2.1ACharge quiescent current: 100uAFull charge voltage: 4.2V+-1%Discharge current: 0-2.4ADischarge quiescent current:50uADischarge conversion efficiency: MAX 96%Output voltage: 5VOutput current: 0-2.4AOperating ambient temperature: -20?to +85?Size: 25x16x4mmPackage Includes:1 x?5V 2A Charge and Discharge Boost Module 3.7V/4.2V