The Bosch BAT181 is a 18V 2.4 Amp-Hour BLUECORE Battery. The BLUECORE Batteries can charge in 30 minutes. Other batteries can take up to 3 hours to charge when hot. BLUECORE Batteries were engineered with internal cooling rods placed between the battery cells to absorb damaging heat. The battery cells stay cooler during operation and charging as compared with standard batteries which heat up quickly, speeding up chemical breakdown and shortening battery life. BLUECORE Battery can charge in 30 minutes while other batteries take up to 3 hours to charge when hot.