The Kanstul ZKT 1503 Signature Series Bb Trumpet is well suited for all-around professional players, and is perfect for solo and orchestral work. The ZKT 1503 trumpet features a .460-inch bore with a #25-O leadpipe and matching #72 taper bell for a dark, powerful sound. The Kanstul 1503 trumpet also features Monel valves with metal valve guides for excellent action.