XC 4.0 extended capacity battery pack features superior pack construction, electronics and performance to deliver more work per charge and more work over pack. 4.0 amp-hours of runtime. Runs cooler and performs in climates below 0° F/-18° C.Features overload protection to prevent you from damaging your cordless power tools in heavy-duty situations, while the discharge protection prevents cell damage. The temperature management system and individual cell monitoring help maximize battery life. Fuel gauge onboard displays remaining runtime for less downtime on the job.