I've got possibly an easy question: did Haynes make more than one model silver/metal clarinet -- i.e. something other than the Thermocouple? I've got two (of allegedly 334) Thermocouples posted in my Gallery. One is stamped with "Pat. Applied For" and the other has the full patent stamped. Note that the keywork differs a bit, too. I then see this one pop up on eBay. I can try to convince myself that one of the pictures might have "Reg Trade" stamped, but it's really too beat-up to tell. The horn does look like it's got the "louver" that's described in the PM Woodwind article I linked to, tho. I'm essentially just interested enough to ask the question .