The Bach 42T Stradivarius Trombone with Thayer Valve F Attachment has a more open feel from other trombones. The Bach 42T Thayer valve eliminates restriction from the open wrap tubing of the F attachment. The 42T is available in yellow brass (42T), yellow brass and lightweight slide (LT42T) or with a gold brass bell (42TG) and gold brass bell and lightweight slide (LT42TG).