Built-in dual IC detects cell voltage. And don't forget the number of uses! Battery detection and protection: overheat protection, overvoltage protection, undervoltage protection, overcurrent protection, overcharge protection. Stable quality and anti-vibration. The best partner of torque wrench, impact drill and angle grinder. The PCB size may change due to changes in the supply chain and processing technology. White characters: random characters, do not accept the specified characters Color: blue Material: PCB Package Contents: 4 x Lithium Battery PCB Board Only the above package content, other products are not included. Note: Light shooting 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 +/- 1-3 cm.