Features: When the battery voltage is under 3V, it enters trickle charging mode and charges the battery with charging current of 100mA. When the battery voltage is greater than 3V, it enters the constant current charging mode and charges the battery with the set constant current charging current. When the battery voltage is close to 4.2V and the charging current is less than 300mA, the battery enters the constant voltage charging mode. After entering the constant voltage mode, stop charging every four minutes, and check whether the battery voltage is higher than 4.15V. If it is higher than 4.15V, stop charging, otherwise, continue charging, and then test after another four minutes. When the battery is fully charged, if the battery is detected to be lower than 4.1V, the preferential turn on to charge the battery. Specifications: Material: ABS Chip: IP2312 Input: 4.5-5.5V Charging Current: 3A Transfer Efficiency: 3A 93%, 2A 94%, 1A 95% Size: Approx. 3.3x1.5cm/1.30x0.59in Note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1x Charging Board