This product is a component, without a battery core. It is used for repairing and battery pack, people who are familiar with battery performance, and have practical experience in battery assembly. Mounting:(1). If a new core is used, please note:A. 18650 power lithium battery core must be,B. 5/10 core group must be equipped with resistance and capacity to make their voltage the same. (2). If the old battery is repaired, test the voltage at both ends of each cell. If the voltage is different, charge each cell to the same voltage value. Very important: That the voltage of each cell is the same PCB welding. This is a plastic case, it can fill 10pcs 18650-ion batteries,Not included rechargeable batteryColor: BlackMaterial: PlasticPackage Content: 1 x Set Battery Plastic CaseOnly the above package content, other products are not included. Note: The light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowed measurement error is +/- 1-3cm.