The 10-inch red brass bell with wire-reinforced rim in the Holton TR-181 produces an outstanding tone and offers great dynamic control and range. A 0.562-inch bore in this Holton True Bass Trombone enhances resonance and richness in sound. This Holton Trombone features a one-piece precision-machined tapered rotor and bearings that offers a smooth and airtight fit. This Holton True Bass Trombone has a chrome-plated nickel-silver inner slide and outer slide making it extremely durable. The ...