Stethotracer, a modern copy?

[transmaster]

I remember there was a kit for something like the Don Bosco Stethotracer. there was also a cheaper version called the "Mosquito" these, as you know, where a signal tracers that where built into what looked like a fountain pen with a ear piece to listen with. The device I remember was built in a narrow circuit board that could be used as it or placed in some sort of home brew case. I cannot think of a search term that will get to it. Does anyone remember it? Hopefully it is still available. As a teenager in the late 1960's I remember Hamradio Gods of radio repair with these "pen things" in their shirt pockets. I would love to get something with the functionality of the Stethotracer, or the Mosquito originals are available but they have become collector's items and are worth more then I am willing to pay for one.