Li-ion Battery Box with Balanced charging PCB For 18V BL1820B BL1815 BL1830. It can fill 5 pieces of 18650 li-ion batteries with LED battery status indicator. But this is only a shell, there is no battery inside. Balanced charging fuction: through the battery management system, ensures that the voltage of each battery cell is basically consistent, ensuring that each battery cell is fully , avoiding certain cell voltages being too high or too low, improving energy utilization efficiency, ensuring the performance of the battery pack, and thus extending the service life of the battery pack. No-Original, New, No Battery Cell !!!!!! DIY (semi-manufactured goods, No battery!) Advance notification: (1). To use this product, you need to have some professional knowledge and experience. We do not that you can use it well. (2). It requires you to have assembly tools. If you do not have these tools, please do not place an order! (3). The label and nickel may not be exactly the same as shown in the following picture and may change with the batch. Very important: that the voltage of each cell is the same before welding PCB. Please be kindly noted: (1). PCB color may be any color according to our stock, (2). PCB design may change with the same function and performance guaranteed. (3). The number and position of components on the PCB may change and be adjusted. Kindly reminder (Very important !!!!!!!): 1. there are no batteries in the package !!!!!! 2. If you need batteries, please don't place orders ! 3. If you don't have the knowledge of battery assembly, please don't place an order ! Color:Black Material:ABS Package Contents: 1 * Li-ion Battery Case 1 * PCB Circuit Board(The color is random, and the designation is not accepted) 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.