Milwaukee M18 48-11-1815 Compact 18V 1.5 Amp Hour Red Lithium Ion Battery w/ Onboard Fuel Gauge FUEL GAUGE: An LED status bar on the front of the unit lets you know how much charge you have left in increments of 25% FADE-FREE POWER: This battery will run at full power until it is completely drained. This lets you work your jobsite responsibilities with consistency COMPACT SIZE: Thanks to its light weight and compact size, youll be able to handle your tools with greater ease with minimal strain on your joints during longer jobs EXTREME TEMPERATURE PERFORMANCE: This battery can be stored and will function at temperatures below freezing and over 100 degrees Fahrenheit (37.78 degrees Celsius) REDLINK TECHNOLOGY: Onboard intelligence allows this battery to cross-communicate with whichever power tool it is attached to. This allows the battery to tell if your tool is going to overheat, so it will put out less power to offset potential damages RED LITHIUM advantage performance: Up to 40% More Run-Time, 20% More Speed, 20% More Torque 1.5 Amp hour - 27 Watt hour battery; Battery fuel gauge displays charge status on tool Durability: Operates Down to 0F, Runs 20% Cooler, Up to 50% More Recharges Equivalent run-time with 40% less weight than a "compact" 18V NiCd battery; Lithium-ion battery delivers long life and run time with fade-free power Best in class construction, Integrated weld frame, Cell separator, Impact and vibration protective rubber