The Milwaukee M18 REDLITHIUM HIGH OUTPUT XC6.0 Battery 2-Pack System Starter Kit. The M18 REDLITHIUM HIGH OUTPUT XC6.0 Battery Pack provides 50% more power and runs 50% cooler vs M18 REDLITHIUM XC battery packs. The optimized combination of size and increased power provides a great solution for the entire range of M18 products. It delivers fade free power and runs substantially cooler through heavy applications, allowing tradesmen to push their cordless tools harder and longer than ever before. The M18 REDLITHIUM HIGH OUTPUT XC6.0 provides increased power in extreme cold...