The MicroStatic tweeter array has been discussed in these pages several times. I'm a fan. I think Frank is too. Some other members not so much. I've owned and refurbished several but sold my last working pair. All I had was one working orphan and a pair I'd foolishly bought "not working". I thought maybe it was a crossover component but it turned out all 8 drivers were fried.  The MS-1 had Peerless tweeters. The very earliest ones had 2 sizes: Larger diameter on the outside and smaller