This model is a solder-free mobile power bank DIY material (circuit board + case) not inclduing battery and packing box, the battery needs to be purchased separately, you need to source 18650 (flat head) battery before assemble finish product. Please note that the capacity of 3 batteries must be consistent, pay special attention to the direction of the battery, wrong direction would cause damage of the PCBA board, (shrapnel is positive, spring is negative) . Please make sure to put in correctly, as there is no second chance, the shell can not be disassembled twice, please get it right at once!