Amazon.ca Product Description BOSCH CoolPack batteries have a unique design that incorporates advanced, heat-conductive housing that significantly reduces heat buildup while you work. This results in a more efficient battery pack that stays cooler, while giving you up to 2x the battery life and 65-percent more run time compared to existing 3.0Ah batteries. State-of-the-art 4.0Ah Lithium-Ion battery technology plus the Bosch exclusive Electronic Cell Protection (ECP) system guarantees optimal tool and battery performance even in tough work conditions. From the Manufacturer Bosch CoolPack batteries have a unique design that incorporates advanced, heat-conductive housing that significantly reduces heat buildup while you work. This results in a more efficient battery pack that stays cooler, while giving you up to 2x the battery life and 65-percent more run time compared to existing 3.0Ah batteries. State-of-the-art 4.0Ah Lithium-Ion battery technology plus the Bosch exclusive Electronic Cell Protection (ECP) system guarantees optimal tool and battery performance even in tough work conditions.