Duracell originated via the partnership of scientist Samuel Ruben and businessman Phillip Rogers Malory in 1920. Duracell manufactures alkaline batteries in many sizes, such as AAA, AA, C, D and 9V. Lesser-used sizes such as AAAA (primarily used in specialty electrical devices, pagers and blood glucose meters) and J size batteries (for hospital devices and photographic strobe flash units) are also manufactured along with a range of "button" batteries using zinc-air, silver-oxide and lithium chemistries, used in calculators, computer equipment, industrial instruments, watches, hearing aids and other small (mostly medical related) devices.