Shown above is the radio service shop of Charles Hurt of Elkhart, Indiana, in 1940, shown here in the August 1940 issue of Service magazine.  He had been in business for a number of years without really making a living, and realized that he had to make some changes. He figured out that to be profitable, he had to make a profit on every single transaction, and he established a bookkeeping system to make sure that happened.

He also realized that there was fierce competition in his area, any one of which were able to press their advantages and force him out of business. The answer was to expand his service area and do it efficiently. Therefore, he purchased the trailer shown here, made it his shop, and adopted the slogan “service at your door.”

Hurt is also shown in this illustration in the December 1940 issue of National Radio News, which notes that the arrangement was also advantageous to the customer, as they avoided charges for pickup and delivery. This item also reveals that for AC power, the trailer was equipped with a dynamotor and storage battery.