G tuning slide for the second valve. Fits model 50B3O bass trombones (open wrap with double inline rotary valves). Replaces the original Gb slide. When installed, the second valve alone gives bottom line G (fundamental of pedal G) in first position. Combination of both valves gives low Eb in first position (instead of low D). This slide is shorter than the standard Gb slide. When used with both valves operated, it places low B (B1) in 7th position instead of flat 5th. Unlacquered. May require slightadjustment for a smooth fit.