General description It can hold 15 pieces of 21700 Li-Ion batteries. This product is a shell only; no batteries are included. It is designed for use with Zhipu Hongsong Jingmi non-original 18V Lithium batteries and is intended for individuals familiar with battery performance and assembly. Technical specifications Capacity: 15 x 21700 Li-Ion batteries Material: Plastic Color: Random (Blue, Green, Red, etc.) PCB Specifications: Built-in IC detects cell voltage current Protection features: Overheat protection, overvoltage protection, undervoltage protection, overcurrent protection, overcharge protection Measurement allowed error: +/- 1-3 cm Installation Preparation before assembly: If using a new core, ensure that the 21700 power lithium battery core is equipped with resistance and capacitance to balance voltage. If repairing an old battery, test the voltage at both ends of each cell and charge them to the same voltage before welding the PCB. Ensure that the voltage of each cell is the