The wide-awake service man 85 years ago could increase his profits by modernizing his customers’ sets with the addition of pushbutton tuning. It was a simple matter, since the pushbutton assembly was available as a unit, and installation consisted of connecting three wires.

After the unit was installed, the individual trimmers were set for stations. One button disconnected the unit and allowed the user to use the main tuning dial. This item appeared in the May 1938 issue of Radio Craft.