OP4040 Lithium Battery Case with PCB Protection Circuit Board for 40V Battery. It can fill 20 pieces of 18650 power Li-ion batteries. But this is plastic shell, there is no battery inside. No-Original, New, No Battery Cell !!!!!! This product is component without battery core. DIY (semi-manufactured goods, No battery!). It is used to repair and assemble batteries pack, only for people who are familiar with battery performance and have practical experience in battery assembly. Notes: After combining the battery pack and this protective board, if there is no voltage output during the initial power on, please activate it with a dedicated charger. 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! Preparation before assembly: (1). If a new core is used, please note: a. 18650 power lithium battery core must be , b. A group of 5/20 cores must be equipped with resistance and capacitance to make their voltage the same. (2). If the old battery is repaired, please test the voltage at both ends of each cell. If the voltage is different, please charge each cell to the same voltage value. (3). The 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. Color:Black Material:pla Package Contents: 1 * Battery Plastic Case 1 * Protection 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.