1. Micro USB input terminal with a female, can be directly input to do with the phone charger rechargeable lithium battery, And still retains the input voltage wiring pads, can be very convenient DIY. Charge module: Linear charging - Current: 1A adjustable Charge precision: 1.5% Input voltage: 4.5V-5.5V Full charge voltage: 4.2V Led indicator: Red is charging / Blue is full charged Input interface: micro USB Work temperature: -10° ~ +85° Inversed polarity: NO Size: small to 25X19X10mm The module current adjustable as long as you change the fixed resistors in the circuit board , then can change the output 100mA-1000mA, very convenient. Note: Ampere meter can only be connected to 5v input end of the module. It is better that the charging current is 37% of the battery capacity. If you charge to the battery of 1000mAH, current of 400 is enough. The connection wire should not be too thick. Make sure the connect point is good. 5 NO Reveral polarity. 5. No over charging to avoid burn damage to chip. Hayatec is UK Registered Trademark of DHD Ltd.