6M, 26M Connqueror, or 28M Connstellation. The 6M and the 26M are basically the same horn, only the Connqueror had a few extra adjustments and more detailed engraving, etc. The 28M Connstellations are very rare. They were only made a couple years before Conn pulled the plug on them. The horn was designed mostly by Santy Runyan. I play a 1950 Conn 6M with the underslung neck. I had mine relacquered. It plays like a dream, and the sound is incredible!