Lrg Silent Phone
You could probably making a bundle of cash making updated ones for cell phones, hehe – Popular Mechanics 1941 – Link.

  • AdamEngelhart

    This is actually a historically important device: it’s called a Hush-A-Phone. Back in the bad old days when you got all your phone equipment from The Phone Company, it wasn’t quite clear whether this sort of thing (attaching a third-party device to a telephone) was legal. An AT&T lawyer saw an ad for it in a window and decided to sue. They lost on appeal, clearing the way for Makers to hook up whatever they wanted to their phones.