SR44

LR44 is the IEC designation for an alkaline 1.5 volt button cell, commonly used in small LED flashlights, digital thermometers, calculators, cameras, calipers, watches, clocks, toys, multimeters, and laser pointers.

The battery nomenclature is defined by the International Electrotechnical Commission (IEC) in its 60086-3 standard (Primary batteries, part 3 Watch batteries). The letter "L" indicates the electrochemical system used: a zinc negative electrode, manganese dioxide depolarizer and positive electrode, and an alkaline electrolyte. "R44" indicates a cylindrical ("round") cell 11.4±0.2 mm diameter and 5.2±0.2 mm height.

Manufacturers have their own part numbers for IEC type LR44 batteries including:

Other types of batteries are or were made in the R44 physical size. Formerly, mercury batteries were made as button cells (types MR44 and NR44). Zinc-air batteries type PR44 require exposure to the air to operate. Some hearing aids and budget solar garden lamps contain a rechargeable 40H battery with Ni-MH chemistry and a capacity of approximately 40mAh. While having the same dimensions, these have a nominal voltage of 1.2V, as with many NiMH batteries. They are compatible with many devices that were designed for LR44 batteries, but some devices may not function properly due to the lower voltage. Silver-oxide batteries type SR44 may provide extra capacity compared to LR44 types but have slightly different voltage characteristics. Performance of a device meant to use a silver-oxide battery may be degraded with substitution of alkaline types.

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