Energizer, AA/AAA pro charger, 1500mah with 4 "AA" battery cells Expanded charging information allowing for ease of use, includes a unique design with the integration of sound to alert the user throughout the charging experience & when there is a bad battery, integrating sound into the design of the charger allows for a series of beeps to indicate that the charging has initiated & when the battery is fully charged, helps to maximize battery performance.