Friedrich Wolff is usually credited with having introduced the first commercial tanning units at this time, and was soon joined by others. In the United States, the first units to become popular were pure UVB booths, the same units designed for dermatological use. They actually find their initial use for tanning in the late 1960′s. However, these units were inherently difficult to control and were replaced in the late 1970′s by the UVA tanning systems developed in Europe.
The original units developed in Europe were very low in UVB, often in the 1 percent or less range. Since then, the United States market has developed new lamps. The majority of lamps used in the U.S. market today are now in the 5.0 to 9.5 % UVB range. Understanding the tanning process, it is not difficult to understand why the marketplace has driven the development of lamps towards a system which more closely resembles that of natural sunlight while maintaining tanning schedules with reasonable tanning times.