M18 18-Volt Lithium-Ion HIGH OUTPUT CP 3.0 Ah Battery Pack (4-Pack)The Milwaukee M18 REDLITHIUM HIGH OUTPUT CP3. 0 Battery Pack provides 50% more power and runs 50% cooler than most other batteries. The result is the same power and runtime of a M18 REDLITHIUM XC battery with a lighter, more compact package. It delivers fade free power and runs cooler through even heavy applications, allowing you to push your cordless tools through a wide range of jobs. This battery is fully compatible with all 200 plus Milwaukee M18