Universal Fast and Smart Charger is designed for charging any NiMH / NiCd Battery Pack from 4.8V - 10.8V , e.g. 4 to 9 cells pack. This is one simple charger for all types of battery packs used for RC airplanes, RC cars, and Airsoft . Red LED indicates charging while the Green LED means fully charged. This charger is equipped with short circuit protection: No output voltage from the charger if the battery is not connected.