It can fill 10 pieces of 18650 li-ion batteries. But this is only a shell, there is no battery inside. No Original, new, No Battery Cell !!!!!! This product is component without battery core. 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. High temperature protection during charging and discharging; low temperature charging protection. Overcharge detection protection. Over-discharge detection protection. Three-level overcurrent protection. If there is no voltage output during initial power-on after combining the battery pack and this protection board, please activate it using the dedicated charger. Temperature control parameters are externally adjustable. Externally adjustable in the first and second stages of overcurrent delay. Battery disconnection protection function. resistor disconnection protection function. Short circuit protection function. Preparation before assembly: If a new core is used, please note: a. 18650 power lithium battery core must be , b. A group of 5/10 cores must be equipped with resistance and capacitance to make their voltage the same. Usage and Assembly Precautions: 1) When soldering battery leads/sampling points, be careful not to connect incorrectly or in reverse. If an incorrect connection is found, the circuit board may be damaged and needs to be retested before reuse; 2) During assembly, the should not directly contact the of the battery cells to avoid damaging the battery cells. Assembly should be firm and reliable; 3) Electronic equipment used for soldering must be reliably grounded, and electrostatic protection should be taken into account to prevent leakage and static electricity from damaging the protection board; 4)During use, avoid contact with components on the circuit board using leads, soldering irons, etc., otherwise the circuit board may be burned; 5) During use, attention should be paid to anti-static, moisture-proof, and waterproof measures. Color: Black Material: plastic Package Contents: 1 x lithium battery case 1 x PCB Protection Circuit Board (The color of the protection plate is random, no specified color is 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.