General description This 18650 Li-Ion Battery Case Box features a protection circuit board (PCB) designed for Zhipu Hongsong Jingmi Lithium Ion batteries. It can hold up to 5 pieces of 18650 li-ion batteries and includes an LED battery status indicator. Please note that this is only a shell and does not include batteries. Technical specifications PCB Specification: Built-in IC detects cell voltage and current, and remembers the number of uses. Protection features: Overheat protection, overvoltage protection, undervoltage protection, overcurrent protection, overcharge protection. Color: Black & Red (PCB color may vary based on stock). Material: Plastic. Measurement allowed error: +/- 1-3 cm. Installation Preparation before assembly: If using a new core, ensure that the 18650 power lithium battery core is used, and that all cores are equipped with resistance and capacitance to equalize their voltage. If repairing an old battery, test the voltage at both ends of each cell. Charge each