- Used for remote car
- Used for smart tag used at toll plaza
- Used for smoke detectors
- Used for security appliances
- Used for walkie talkies
The nine-volt battery or 9-volt battery, in its most common form was introduced for the early transistor radios. It has a rectangular prism shape with rounded edges and a polarized snap connector at the top. This type is commonly used in walkie talkies, clocks and smoke detectors. The nine-volt battery format is commonly available in primary carbon-zinc and alkaline chemistry, in primary lithium iron disulfide and in rechargeable form in nickel-cadmium, nickel-metal hydride and lithium-ion. Mercury-oxide batteries of this format, once common, have not been manufactured in many years due to their mercury content. Designations for this format include NEDA 1604 and IEC 6F22 (for zinc-carbon) or MN1604 6LR61 (for alkaline). The size, regardless of chemistry, is commonly designated PP3 - a designation originally reserved solely for carbon-zinc - or in some countries, E or E-block. Most nine-volt alkaline batteries are constructed of six individual 1.5V LR61 cells enclosed in a wrapper. These cells are slightly smaller than LR8D425 AAAA cells and can be used in their place for some devices, even though they are 3.5mm shorter. Carbon-zinc types are made with six flat cells in a stack, enclosed in a moisture-resistant wrapper to prevent drying. Primary lithium types are made with 3 cells in series. In 2007, 9-volt batteries accounted for 4 percent of alkaline primary battery sales in the US. In Switzerland in 2008, 9-volt batteries totaled 2 percent of primary battery sales and 2 percent of secondary battery sales.