It is communication technology that allows the tool and battery to exchange data in real time and monitor conditions during use to protect against overloading, over-discharging and overheating.
overvoltage:if battery with lower voltage,the cordless wrench will stop,please charge the battery
overcurrent: if stop as generate very larger current,loosen the switch,work again
overheating:in extreme work cases, the electric wrench will stop as higher temperature,please wait the battery to normal temperature,maybe it need some minutes
over-discharging : the charger will stop to charge after fully battery