Labels:bannister | trolleybus OCR: The Trombone AND RELATED INSTRUMENTS ROMBONES are brass instruments with long cvlindrical tubes, flared bells, and cup-shaped mouthpieces Most trombones have a slide that the player uses to alter the length of the tube and change the pitch, but some have valves TROMEOHE VALVE TROMBONE ACKBUT cylindrical moutl thpieces TALVE SACKBUT