Features of the BL1840: Unbeatable 36 minute charge time. Up to 33% extra runtime and extended battery life. Same size and weight as 3.0Ah BL1830. Works with your current Li-ion chargers. Computer controlled optimum charging. Compatible with starred terminal machines. Compatible with yellow terminal machines. Cooling System for max battery life. Battery protection circuit. Features of the DC18RC: The DC18RC has a cooling fan and Active 3 Controls. This means that during the loading of the charging voltage, charging current, and temperature is held in the holes. The cooling system blows cool air into the battery. As a result, high temperatures occur in the battery, so that the battery life is extended, and the charging process is accelerated When used in conjunction with charging adapter ADP03 this charger offers also the possibility of charging Ni-MH slide on batteries of 9.6V to 24V batteries or when used with charging adapter ADP04 this charger offers the possibility to charge Ni-Cd and Ni-MH rod and block batteries of 7.2V to 18V batteries. This set includes 1 x BL1840 4.0ah Battery 1 x DC18RC Charger