It can fill 15 pieces of 21700 li-ion batteries. But this is only a shell, there is no battery inside. Suit for DeWalt 20V For FlexVolt 60V Lithium Battery. 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. No-Original, , No Battery Cell !!!!!! Advance notification(Very Important): 1. Color: Blue, or Green, or Red, etc. any color, PCB color and version number are different according to the actual latest inventory. 2. PCB design may change due to changes in the supply chain and processing technology. 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. Precautions for use and assembly: 1) When welding battery leads/sampling points, be careful not to connect them incorrectly or in reverse. If a wrong connection is found, the circuit board may have been and needs to be retested before it can be used again. 2) During assembly, the BMS should not directly contact the surface of the battery cell to avoid damaging it. The assembly should be firm and reliable. 3) Electronic devices used for welding must be reliably grounded, and attention should be paid to electrostatic protection to prevent damage to the protective board caused by electric leakage and static electricity. 4) Be careful not to touch the components on the circuit board with lead wires, soldering iron, etc. during use, otherwise it may burn out the circuit board. 5) During use, attention should be paid to anti-static, moisture-proof, and waterproof measures. Note:due to different production batches, there are differences in printing screen printing, which does not affect the use. Colour:Random Color(random colors, don't accept the specified color) Material:PCB+Plastic<br