The flats on the stem remind me of the ones on the 'Maestro' trombone F-attachments. Was JinBao in business back them?
Dan Schultz
"The Village Tinker" http://www.thevillagetinker.com" target="_blank
Current 'stable'... Rudolf Meinl 5/4, Marzan (by Willson) euph, King 2341, Alphorn, and other strange stuff.