Milwaukee 48-59-1204 - M12™ 4-Bay Sequential ChargerLess swapping, more charging. The M12 four bay sequential charger reduces the amount of time spent changing out batteries, increasing productivity on the jobsite. Its slim design makes it the perfect solution for a bench top, as well as storage and transportation of packs on and off the jobsite. Featuring REDLINK Intelligence, it communicates directly with the battery to monitor cell voltage, temperature, and charge status to optimize the performance