1. Built-in IC detects cell voltage current. And remember the number of uses! 2. Detection and protection battery:Overheat protection, overvoltage protection, undervoltage protection, overcurrent protection, overcharge protection. 3. all the series of achieve low voltage shutdown. Cooperate with many power tool factories! 4. PCB design may change due to changes in the supply chain and processing technology. 5. Suit for Zhipu Hongsong Jingmi (no Original ) 18V Lithium Battery; note: 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. Preparation before assembly: 1. If a core is used, please note: (a). 18650 power lithium battery core must be ; (b). A group of six cores must be equipped with resistance and capacitance to make their voltage the same. 2. If the old battery is repaired, please test the voltage at both ends of each cell. If the voltage is different, please charge each cell to the same voltage value. Very important: that the voltage of each cell is the same before welding PCB. Specifications: 10-Hole colour: black Material: plastic Package Contents: 4 set x Battery Case Due to Different production batches, Some accessories have different colors and appearances, but have the same function 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.