I'm not surprised. When I did a search for that item, I found new ones in the box for sale on eBay. I didn't know what the name of the company was, but found it through my search. As a young girl of about 10, I'd never seen anything like it before, and it stuck with me all these years.
Funny story for this evening: my dad flew to Missouri to help his elderly aunt and uncle. While out of town, he called my mom morning and evening to catch up. The morning calls always had a horrible hum. The evening calls were fine. My mom asked me to help diagnose the problem. I came by in the morning when the hum was present. After checking a few spots, I unplugged a 25 ft extension cord that went from the front door, down the wall, behind a chair and connected to a phone in the living room. The hum stopped. I traced the wiring behind the chair to find an old 4-pin phone plug and jack. It was discolored. On closer inspection, the discoloration was cat urine. The cat had been peeing on the connector every morning coupling the princess telephone power on the yellow/black pair into the tip/ring green/red pair. By afternoon, the pee had dried and the coupling wasn't apparent. I "retired" the extension cord to the trash can and replaced the plug on the phone. End of problem.