The Milwaukee M18 Red Lithium 9.0 Starter Kit with 2 Batteries (48-59-1890P) delivers up to 5 times more run time, 35 percent more power, and operates 60 percent cooler than standard 18V lithium ion batteries. In addition to running substantially cooler than other batteries, it also maintains full power during heavy applications. The integrated Redlink Intelligence system provides overload protection for the tool, battery, and charger. The Rapid Charger charges up to 40 percent faster than other chargers, reducing downtime and improving productivity.The Red Lithium High Demand 9.0 Battery Packs are fully compatible with over one hundred Milwaukee M18 cordless power tools.