Although these cars were always rare in North America, surprisingly about 285,000 were made between 1955 and 1969. An unknown quantity were actually exported to the US for the first 6 years of production. We thought Volkswagens were small!
Power was supplied by a rear mounted 2 cylinder 2 stroke engine in sizes of 250, 300 and 400cc giving a top speed of about 60mph.
The company was located in the town of Dingolfing, Bavaria and was bought by BMW in the mid sixties. I believe the ad is from 1957 as the 400cc engine was new that year.