An AM/FM pocket radio, probably from the 1980s. I haven't been able to find anything about the history of this radio online. The only way to listen to it is via the headphone jack. It appears to use the headphone wire itself as an antenna. My brother and I used the one photographed when we were kids, and I recently began using it again from time to time.
The battery door was lost a long time ago. We'd been using tape to hold in the batteries, which left a bunch of residue visible in the photos. (I've tried removing it with rubbing alcohol, but it's pretty well-bonded with the radio at this point.)
I designed a battery door replacement in OpenSCAD and printed it in red, as that was the filament I had loaded. It goes well with the red accents on the front.
If you happen to need a replacement RP40 battery door, you can download the STL file and print your own. (Make sure you print it oriented as-is, with supports.) If you want to make modifications or use my work as a jumping off point for designing a similar battery door, you can download the SCAD file. This work is covered by the Peer Production License. These files are also available on Printables.