c.1960 Constant "Hi-Delity" 6T-330
Shirt pocket radio, thermoplastic cabinet
3 11/16 x 2 7/16 x 1 inches / 94 x 62 x 25 mm
Six transistors (Toshiba), superheterodyne circuit
Three teeny 1.5v UM-5 cells
Manufactured by Fuji High Frequency Radio Lab. Co., LTD. (Constant), Japan
So sweet, so small and so thin! — this is certainly one of the classic Japanese shirt pocket radios — not rare, not early, just simply a great example of the idea of the "Japanese pocket radio".
Constant also sold this radio under the names of "Imperial", "Jupiter", and probably several other names as well.