Detrola was the largest Michigan radio manufacturer, and was in business from 1931 until 1948. They grew from nothing into one of the largest radio manufacturers in just a few years time. Detrola built radios under a variety of private brand names as well as under their own name. As much as 90% of production was private brand names. In the late 1930’s, Detrola proclaimed in their advertising that they had the world’s 6th largest output of radios. Many of the brand names they built were for regional or local stores and therefore had limited distribution. It is estimated that there are over 100 brand names that were built by Detrola.