The inside of this radio is almost as beautiful as the face. In addition to the six Hitachi oval transistors, (HJ23, HJ-22 x 2, HJ-15, HJ-17X2), you can see the early glass Hitachi 1N34 diode at the lower right of the circuit board. Hitachi's soft plastic "leak-proof battery cases" were also pretty slick. They have a cap at one end and the holes at each end are just large enough to allow the batteries to make contact. You will find these battery cases in a couple of other early Hitachi radios as well, including the TH-667 and WH-667.