NINEVOLTBATTERY
Nine-volt battery
The most common form of nine-volt battery is commonly called the transistor battery, introduced for the early transistor radios. This is a rectangular prism shape with rounded edges and a polarized snap connector at the top. This type is commonly used in pocket radios, smoke detectors, carbon monoxide detectors, guitar effect units, electro-acoustic guitars and radio-controlled vehicle controllers. They are also used as backup power to keep the time in certain electronic clocks. This format is commonly available in primary carbon-zinc and alkaline chemistry, in primary lithium iron disulfide, and in rechargeable form in nickel-cadmium, ...The above text is a snippet from Wikipedia: Nine-volt battery
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