Initially founded in 1906 in Wisconsin, the first Ray-O-Lite batteries for engine ignition and for operating telephones. It was not until 1921 when the Ray-O-Vac name was used, in reference to dry batteries for use with vacuum tube radios. Since that time, Rayovac has expanded into power sources for portable electronics, furthered by hearing aid and flashlight production, with many acquisitions and innovations along the way. As a part of Spectrum Brands, they currently sell a wealth of AA and AAA batteries, as well as 9V and coin batteries for countless portable electronics. Rayovac also produces portable power chargers, reusable batteries, lantern batteries, and emergency hand-held and lantern lights.