1. Ultra-small size design, easily embedded in smart wearable, micro-drone and other compact space 2. Constant current/constant voltage charging mode, to ensure that the charging rate is maximized and to avoid the risk of overheating 3. Supports automatic re-charging function, to keep the lithium battery always in the best state 4. Accurate charging voltage 4.2V (±1%), to protect the battery safety and prolong the service life of 5. Trickle charging threshold of 2.8V, to effectively protect the low battery back to a healthy state Product Name: Mini Li-ion Battery Charging Board Module Charging Current: 600mA Charging Voltage: DC 4.2V (±1% accuracy) Trickle Charge Threshold: 2.8V Functional Characteristics: 1. Constant Current / Constant Voltage Charging Mode with Thermal Adjustment to Ensure Maximized Charging Rate while Avoiding Overheating 2. Charging Current Monitoring Output to Support Power Monitoring 3. Monitor output 3. Automatic re-charge function Size: 10x7.5x5.2mm Description: Ultra-small extreme design. This 3.7V Li-ion battery charging pad is easily embedded in compact spaces with its ultra-small design for smart wearables, Micro-type drones, loT devices, electric mosquito swatters, etc., and it can even be tucked directly into the space of a usual charging cable head. The positive and negative poles can be used by connecting the positive and negative poles of the lithium battery. Minimalist design, extreme performance one by one, let every inch of space play a value, for creative technology products injected into the soul of efficient battery life. Color:As Shown Material:Metal Package Contents: 50 * Lithium Battery Charging Board Only the above package content, other products are not included. Note: Light reflection 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.