I have no idea where these came from. I moved recently and found them in with some computer gear from a couple of years ago...I'm thinking I bought them locally to have extra mics for my band at the time and maybe for live recording.
honestly, they're brand new, built like a tank (even the grilles). I hooked them up and they sound like a sm58 to me (I've used a beta58 for years, a reg sm58 for years before that).
$30 shipped for the pair.
here's the mf page on them in a package:
http://pro-audio.musiciansfriend.com...e-1?sku=277094
pdf:
http://www.nady.com/manuals/microphones/sp9.pdf
pic below