What is this Zenith "Wavemagnet"?

I recall those antenna things being sold on TV back in the late 60's thru the mid 70's. They had a cylindrical tube on top of the wall plug. They had been blamed for starting fires and the later versions had one plastic prong instead of 2 metal ones. Did any of these actually work?


Think of all the cheap bastards who probably tried to connect their TV's antenna terminals directly to the wall socket!

Anthony