Ditch the gas, keep the power with SKIL PWR CORE 40? lithium. The PWR CORE 40? 4.0Ah lithium battery uses patented technology that results in longer runtime and extended battery life. Each cell is surrounded by temperature management material to keep the battery cool and powering on. Use the 40V lithium battery to power up all SKIL 40V tools. PWR CORE 40? LITHIUM BATTERY �C This 40V 4.0Ah lithium battery fuels the power and performance of the PWR CORE 40? system LONGER RUNTIME BATTERY LIFE �C Industry-leading PWR CORE 40? lithium battery technology wraps each cell with cooling material to keep the battery powering on for 25% longer runtime 2X battery life ONE BATTERY, MANY TOOLS �C Pairs with all SKIL 40V power tools ALWAYS KNOW CHARGE STATUS �C Green LEDs show status, so you always know how much charge is available SHOCK-RESISTANT DESIGN �Cnbsp;Provides additional durability to battery cells and electronics