It can fill 5 pieces of 21700 li-ion batteries. But this is only a shell, there is no battery inside. Suit for Zhipu Hongsong Jingmi no-Original for 18V Lithium Battery. 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. Notes: After combining the battery pack and this protective board, if there is no voltage output during the initial power on, please activate it with a dedicated charger. Note:Due to different production batches, some accessories have different colors and appearances, and their functions are the same; The color of the protection board is random, and the designation is not accepted. The appearance and typesetting design of the protection board are different, which does not affect the use. 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. Color: Blue, or Green, or Red, etc. any color, PCB color and version number are different according to the actual latest inventory. 4. 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. 21700 power lithium battery core must be b. A group of 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. Colour:Black & Red Material:plastic 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.