Transistor 4T Label code PR-793

The Zephyr Transistor Z and the Transistor 4T models have non-vented backs, TRANSISTOR on the escutcheon, and a label code PR-793. The only difference between these two models is the round badge: Z or 4T. There is no model number on the models, so the badge is used for part of the model name.

The 2nd IF transistor is reflexed as the 1st AF stage.

Later similar versions of the Columbia 4 Transistor 400B, 4 Transistor 400G, and
4 Transistor 400R have vented backs (probably to correct a heating issue of the germanium transistors),  4 TRANSISTOR on the escutcheon, a label code PR-1018, and a round badge Columbia above a music note. The only difference between these three models is the cabinet color. There is no model number on the models, but it is printed on the box.

In questo link sono elencati 36 modelli, di cui 34 con immagini e 4 con schemi.
Elenco delle radio e altri apparecchi della Zephyr Co., Ltd.; Tokyo