Switching Frequency up to 1MHzQuasi-CV mode to Compensate for the Voltage Loss on Battery Internal Resistance and Trace ResistanceAutomatic RechargeProtection for Battery Voltage Being Low than Input and Short BatteryGood adaptability to Input Supply with Limited Driving CapabilityBattery Overvoltage ProtectionLed indicator : "CR" LED is charge status indicator"OK" LED is fully charged OR Constant voltage mode;Widely usedHigh safety performanceSimple and easy to understand and operateBattery overvoltage protectionOperating Ambient Temperature-40Celsius to +85CelsiusSize 39mm x 18mm x 6.3mmWeight : 5gParameter:4-Cell(4S) 16.8V Version:Input voltage : DC 3-6V(Recommend DC 3.7V 5V)Input current : 2A(2A Version);Charging voltage : 16.8VCharging current : 0.56A(2A Version);Colour:blackMaterial:PC+MetalPackage Contents:1 x Li-Ion Charger ModuleOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.