No Battery Included! This product is a component without a battery core. It is intended for repairing and assembling battery packs, and is only suitable for individuals who are familiar with battery performance and have practical experience in battery assembly. Lithium battery shell sleeve compatible with 10.8V 12V BAT411 BAT420 BAT412A BAT413A lithium battery packs. Holds 3 pieces of 18650 li-ion batteries. This is a shell onlyno batteries are included. 1. What to consider when assembling a battery pack: Ensure 18650 power cells have consistent model, voltage, and internal resistance. Higher consistency is better. For voltage configurations: 10.8V (3S), 14.4V (4S), 18V (5S). The voltage detection wires must be correctly connected. Use high-quality batteries instead of recycled or salvaged cells. A spot welder is required. 2. Replacing the protection circuit board: Before replacing the protection board, measure the voltage of each 18650 cell group to ensure they are balanced. The protection board provides safety functions but does not balance voltages. If the battery pack has unbalanced voltages, simply replacing the protection board will not resolve charging or discharging issues. It is recommended to use matched 18650 batteries. Please note: If you do not agree with the following statements, please do not purchase: (1) PCB color may vary based on available stock. (2) PCB design may be updated while maintaining the same function and performance. (3) The number and placement of components on the PCB may vary or be adjusted. Color: Black Material: Plastic The protection board color is random and cannot be specified. Batteries are not included. Package Contents: 1 x BAT411 Li-ion Battery Case Content limited to items listed above; other products are not included. Note: Lighting effects and monitor settings may cause slight differences in color representation.