The King 3B Plus trombone is built with a classic jazz trombone style in mind. It features a slightly larger .525" bore compared to the standard 3b models, which opens up the horn in all ranges of the instrument. A vintage balancer and deluxe style bell engraving are included on this trombone. A sleek hard shell case protects this trombone when not in use. These king small bore straight trombones have set the standard in jazz performance for generations.