1. The integrated dual IC detects the voltage of each cell. And remember the number of uses 2 Each battery can be detected and protected. Overheat protection, overvoltage protection, overvoltage protection, overload protection.3. The entire new series achieves low voltage shutdown. Cooperate with many factories 4. Stable quality and anti-vibration. It is the best partner of torque wrench and impact drill and angle grinder.Material:PCBcolour:greenPackage Contents:4 x Li-ion Battery Protection BoardOnly the above package content, other products are not included.Note: Light 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.