anyone familiar with these? I have a pair, seemingly brand new/never used in the original boxes and am just trying to figure out what I have -- as far as what era they were produced in, what purpose they were used for (music or dictation or whatever), what sort of quality they are, etc. they both have cables on them that terminate in standard headphone 1/8" jacks, and i've tested them and they both work fine off the plug in power of my D50. Google turned up absolutely zilch...literally 0 results for Magnavox 1A9210. i can take pics if any vintage mic enthusiasts are interested.