It can fill 15 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