This is a plug in module built around a U shaped metal rod which serves as frame, handle and guide pins. There are 2 metal plates attached across the frame. The rear plate has a pair of Amphenol 32 pin finger connectors. The front plate has 8 socketed miniature vacuum tubes and 8 test points. A circuit board located between the front and rear plates has several rows of terminal posts. A variety of discrete components are soldered to the terminal posts on both sides of the board. The front plate has "TOGGLE A" printed on it.