Lithium battery not included! only f people who are familiar with battery perfmance have practical experience in battery assembly. The PCB protection board with voltage detection to prevent overcharge over discharge, safe to use. Help to repair assemble battery pack. Place 15 18650 power lithium batteries, But this is a plastic shell, there is no battery inside. No Cell, DCB609 Plastic Case F 20V 60V FlexVolt lithium Battery DCB612 Preparation befe assembly: 1. If using a new ce, please note: (1). Please use 18650 power lithium batteries with small internal resistance, the same model the same parameters, do not use dinary lithium batteries f energy stage (2). Please test the voltage of a single 18650 battery charge the single battery so that the voltage of each 18650 battery is the same. 2. If repairing an old battery, please test the voltage at both ends of each battery. If the voltage is different, please charge each battery to the same voltage value. Very imptant: Make sure the voltage of each 18650 battery is the same befe soldering the PCB. Due to different batches, there may be differences in product appearance, col, printed text, which will not affect the use. Colour:Yellow Material:Plastic Package Contents: 1 Case Kit Only the above package content, other products are not included. Note: Light reflection different displays may cause the col of the item in the picture a little different from the real thing. The measurement allowed err is 1-3cm.