Bass Trombone With Three Valves
This is certainly not the first bass trombone with three
valves, Larry Minick made several back in the 1970s.  He
had also made a bass version of Holton's Superbone idea
(tenor trombone with full length hand slide and three piston
valves).  The customer that thought this one up wanted
something different.  The unique idea here is to have a bass
trombone that can be played normally with the ability to
convert the valve lengths to be played as a conventional
three valve system, or in other words, a bass Superbone.  
As pictured, it is set up for the latter.  The thumb valve is a
whole step, the second finger controls the half step and the
third finger for the one and one half step valve.  This set up
was easy to use since the only change in fingering is to
remember that the thumb does the job normally done by
the first finger.  That finger is busy holding on to the
instrument through the ring mounted on the hand slide.  
Not shown is a much longer slide for the first valve that
lengthens it to two and one half tones or F as in a
conventional bass trombone.  The second valve slide (third
finger) pulls out far enough to be used as a conventional
second valve on a bass trombone.  Crazy, huh?
Click on image for larger view.