The module is suitable for 3 strings of 3.7V lithium batteries. By short-circuiting, the default is 2 strings. When two strings are used, the module's built-in battery balancing function can be used, which is very practical. The input can be TYPE-C port and welding wire. When the TYPE-C port is connected to a fast charging power source, the charging voltage is automatically adjusted to improve efficiency. If the input voltage is less than the battery voltage when the welding wire is input, the module can only work in the boost state. Output overcurrent, overvoltage, short circuit protection. Supports QC fast charging 15W synchronous switch boost charging Boost charging efficiency 94% Series balanced charging Charging current adjustable Input overvoltage and undervoltage protection Adjustable charging timeout protection Due to different batches, the printed words on the product be different, which does not affect use. Colour:Black Material:PCB Package Contents: 5 * Lithium Battery Charging Boost Module 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.