Bach 42AF Axial Flow Stradivarius Tenor TromboneThe Bach 42AF is the latest and most exciting development in Bach Stradivarius professional trombones. It features the new "Infinity" axial flow valve. This patented valve design eliminates the metal to metal contact found in any other axial flow design through the use of sealed bearings both in the nose and in the back plate. This assures tight tolerances that will resist wear over time. The 8 1 2" one piece hand hammered yellow brass Bach 42 bell