It can fill 20 pieces of 18650 li-ion batteries with LED battery status indicator. But this is only a shell, there is no battery inside. Suit for Lomvum Zhipu Hongsong Jingmi no Original for Makita 18V Lithium Battery. This product is component without battery core. This is only a shell, there is no battery inside. 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. PCB Specification: 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.PCB design may change due to changes in the supply chain and processing technology. Please be kindly noted: If you have any objection to the following two items,please do not order! (1).PCB color may be any color according to our stock! (2).PCB design may change with the same function and performance guaranteed! Preparation before assembly: 1.If a new core is used,please note: a.18650 power lithium battery core must be selected, b.A group of 20 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: Ensure that the voltage of each cell is the same before welding PCB. Colour:Black Material:plastic note:The color of the protection board is random,no specified color is accepted Due to different batches, there may be differences in product appearance and printed text, which will not affect use Package Contents: 1 x lithium battery case with PCB Protection Circuit Board 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.