The Makita DC18RD twin 18v Li-ion charger, charges 2 Makita 18 volt LXT lithium-ion batteries simultaneously. The rapid charge technology selects the optimum voltage and current and temperature is controlled by the forced air system that circulates air through the battery to prevent overheating. and a full charge sound alert confirms when the charge cycle is complete. Built-in fan circulates air through the battery during the charging process to cool the battery for faster charge time Optimizes battery life by actively controlling current, voltage and temperature Full charge sound alert LED charging display Twin charging ports Forced cooling system Electronic current limiter for overload protection