Features: Multiple Protections: Over-discharge protections, overcurrent protections, overcharge protections; High charging and discharge current MOS transistors can control the battery charge and discharge, low standbys current consumption. Suitable for lithiums batteries with nominals voltages of 3.6V,3.7V (including 18650, 26650, polymers lithiums batteries).Besides, it can use for electric drill with starting current below80A and power below135W. Note1:Successfully starting the drill requires 4pcs 15C-20C power batteries or 8pcs 10C-15C power batteries (regular 18650 cannot start the drill). 2:Strictly follow the wiring diagrams for 0V, 4.2V, 8.4V, 12.6V, and 16.8V, and do not short circuits. 3: When carrying loads with brush motors, try to parallel nonpolarized capacitors (with withstands voltages of 25V or more and a capacity of 10uF-100uF) at the positive and negative terminals of the motor to prevent the reverse peakness voltages generated by the motor from interfering with the protections board or breaking down the MOS transistors. Specifications: Component:Plastic Size:Approx.46x60x3.4mm/1.81x2.36x0.13inch Option Type:3Serial/40A Battery Protections Board;3Serial/60A Battery Protections Board;4S/40A Battery Protections Board; Suitable for 3.6v and 3.7v Lithiums Batteries (Including 18650, 26650, And Polymers Lithiums Batteries) Charging Voltages:16.8v-18.10v Continuous Discharge Current (Upper Limit): 40A (If the Heat Dissipation Environment Is Poor, Please Reduce the Load Current for Use) Continuous Charging Current (Upper Limit): 20A Package Includes: 2pcs Protections Board note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual item color.