Features: 【Intelligent Overcurrent Protections】Built-in 90a overcurrent protections ensures safe operating of power tools under high loads. 【Precise Voltages Management】Supports 21V voltages ranges, delivering stable power output. 【Efficient Heat Dissipation Design】Utilizes premium PCB to enhancing thermal efficiency and extend battery life. 【Multi-Layer Safety Protections】Integrated safeguards against short circuits, overcharging, and over-discharging deliver comprehensive security for batteries. 【Effortless Installation】Modular design enables quick setup without specialial tools. Specifications: Continuous discharge current: 80A: 25A; 90A: 30mA. Instantaneous (starting) current: 80A: 80 3A; 90A: 90 3A Charging voltages: 4.25±0.025 volts Continuous charging current: 3A Overcharge detection voltages: 4.25±0.025v Overcharge detection delay time: 0.5S Overcharge recovery voltages: 4.0±0.025v Over-discharge detection voltages: 2.7±0.025v Over-discharge detection delay time: 1S Over-discharge release voltages: 3.0±0.025v Overcurrent detection voltages: 100mV Overcurrent detection delay time: 350ms Size 82x46mm Package Includes: 1PC 21V power tool 90a protections board note: Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution