A PP3 battery, commonly referred to simply as a nine-volt battery, is shaped as a rounded rectangular prism and has a nominal output of nine volts. Its nominal dimensions are 48 mm × 25 mm × 15 mm. The 9v (volt) or PP3 battery is commonly used in a wide range of appliances e.g. smoke detectors, carbon monoxide alarms, pocket radios, radio-controlled vehicle controllers, digital clocks, alarm clocks etc. PP3 actually refers to the type of connection or snap that is on top of the battery . The PP3 connector (snap) consists of two connectors: one smaller circular (male) and one larger, typically either hexagonal or octagonal (female). The connectors on the battery are the same as on the connector itself -- the smaller one connects to the larger one and vice versa. 6 AAAA batteries will be found inside when the battery is open. Using the 6 metal strips inside found on the bottom and top, you can use them in a device that uses AAA batteries.