The Milwaukee M18 REDLITHIUM XC5.0/CP2.0 Battery 2-Pack System Starter Kit. The M18 REDLITHIUM XC 5.0 Ah Battery Pack delivers up to 2.5X more runtime, 20% more power and 2X more recharges than standard lithium-ion batteries. The M18 REDLITHIUM CP 2.0 Ah Battery Pack Delivers up to 2X more runtime, 20% more power and 2X more recharges than standard lithium-ion batteries. These lithium-ion battery packs feature superior pack construction, electronics, and performance, providing users more work per charge and more work over pack life than any battery on the market. Each battery pack is durably built for heavy-duty use, runs cooler, and performs in climates below 0°F/minus 18°C. This protection routes water away from the electronics and out of the battery pack, extends the users' battery run-time and life by minimizing heat, and prevents pack failures from vibration or drops. Built-in REDLINK Intelligence protects the battery from overloads, preventing users from damaging their cordless power tools in heavy-duty situations, while the discharge protection prevents cell damage. An integrated temperature management system and individual cell monitoring help to maximize battery life. In addition to the battery packs, the starter kit includes an M18 and M12 Battery Charger.