they are getting ready to start preorders of version 4.
the modmics are very popular so often sell out rather quick.
its an upstart company selling them not some large corporation churning out millions of them.
http://www.modmic.com/
your best bet is to preorder the new version 4. they do get great reviews on sound quality and really not much on the market compares to them.
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now... as another option you could just look up to see what gaming headset with detachable mic has the best microphone then buy just a replacement microphone boom. then use a 3.5mm female to male cable to connect up to it and zip tie the mic to your headphones (or velcro or other fix) and it does the same thing without being pretty. some people have even modded...