Schilke ST30 Custom Series Small Bore Trombone The Schilke ST30 Tenor Trombone features a .500" bore combined with three interchangeable leadpipes to suit the players needs, progressing in order from tightest (#1) to most open (#3). The ST30 Series also features a choice in bell and outer handslide material to meet the playing needs of the individual. The Rose Brass bell offers a warm, singing sound that works well with solos or ballads, while the yellow brass bell offers a more brilliant sound across all registers that is perfect for lead or section playing. The handslide is available with chrome-plated inner tubes plus an outer slide choice of yellow brass for a slightly warmer sound with more rounded articulations, or nickel for a brilliant sound with more immediate articulated response.