This is probably one of the more rare Sony boomboxes and definitely has one of the cooler names. It is the Sony ZX-7. ZX-7 sounds fast and high tech, almost like a high end race car. And, in fact, it actually lives up to its name. It features a 1.4 multi-volt power supply and high quality Sony APM speakers. For its compact size it can really put out some bass as well. It was released around 1984 and is probably one of the better looking and performing compact boomboxes of that era. Sony says that it puts out 5 watts per channel but most owners feel that it's very loud for its size. Speaking of its size - it is small. It measures about 14 inches long and just a bit more than 4 inches tall and wide.
Note on the closeup of the panel above that the tuning scale starts at 76 and goes up to 108 which is a little strange for FM. The buttons also have a nice dimpled texture to them to make is easier to use them. The ZX-7 manual claims the unit weighs in at around 2.7 kilos or about 6 pounds which is fairly heavy for a compact box like this.
The design of the box is very rectangular and Sony used flat square speaker wide range cones to add to that effect as well. It also incorporated Dolby Noise Reduction B.
The ZX-7 also came with a very cool case in which it fits snugly. The boombox is hard enough to find as it is but the case is even harder to find and definitely adds significant value to the box.
Here's a picture from the Sony manual showing the ZX-7 in its carrying case. Nice!