LITHIUM-ION battery delivers long life and run time with fade-free power. Battery fuel gauge displays remaining run-time Milwaukee REDLINK Intelligence. Overload protection prevents user from damaging their cordless power tool investment in abusive situations. Temperature management system keeps battery in ideal temperature range to provide maximum life. Individual cell monitoring ensures optimal charge and discharge for maximum life. Discharge protection prevents cell damage from over-discharge. Cell separator. Impact and vibration protective rubber. For use with Milwaukee M18 cordless tools.