While the TH-668 may be lengthy, it is slim and well-proportioned. One reason for the length of these early horizontal radios is that makers aimed to achieve maximum battery life by using four C-cell batteries to supply power. Lining the batteries up end-on-end was the most efficient way to implement this, and that meant adding length. The original owner of this sample kept a log of battery changes; it appears the radio required a battery change once every 18 months to 2 years. That's pretty impressive, even if we don't know the owner's pattern of use. You can see the external antenna and earphone jacks on the left side, as well as the sturdy leather carrying case that protected the radio.
The TH-668 is shorter in length and height than its predecessor the TH-669, Hitachi's first transistor radio. (Why Hitachi decided to go backward with the product numbering on these two early models is something we may hope to learn some day.) One of two notable changes in the design of this model is the addition of the hinged plastic carrying handle. Hitachi must have decided a handle similar to those on the portable tube radios would be more practical than a soft strap. And, after carting this radio around a bit, I think the handle was a great addition. The hard handle is easier to grasp, it ages better, and it doesn't require carrying strap stays that jut out at the ends of the cabinet.