The M18 REDLITHIUM-ION BATTERY features superior pack construction, electronics, and performance to deliver more work per charge and more work over the life of the pack. REDLITHIUM-ION BATTERY features an advanced design, protecting the pack against harsh job-site environments. This protection routes water away from the electronics and out of the battery pack, extends run-time and life by minimising heat, and prevents pack failures from vibration or drops.Features and Benefits: Delivers up to 2.5x more run time, up to 20% more power and up to 2x more battery life compared with previous Milwaukee battery technology. (Results depend on tool and application) REDLITHIUM-ION protection with Milwaukee REDLINK digitaloverload protection to prevent users from damaging their cordless power tool investment in abusive situations Individual cell monitoring ensures optimal charge and discharge for maximum life Can be used in extreme temperatures down to -20 C withoutcompromising on runtime and battery life. On-board battery fuel gauge helps the user to maximize his battery runtime efficiency.