I'm looking to sell a Bass Trombone I bought this instrument from Andy Fawbert (BBC Big Band) and has been great but now surplus to requirements now as now playing euph & 'tenor' The serial number is 625xxx which I think puts the date of manufacture to late 70s. On the ornately engraved 9 1/2-inch bell it reads "King Duo Gravis King Musical Instruments USA." It has side-by-side trigger action, nice free moving slide, and the original King case. They literally don't make them like this anymore, great solid sound and projection. Anyone interested before I put on EBAY??