Conn 88HO Symphony trombone features a .547" primary bore with a .562" bore open wrap F attachmnt offers clarity and projection with an open feel. The chrome plated nickel silver inner handslide tubes provide the ideal surface for smooth & quick handslide action. The rose brass material used in the professional bell & handslide material produces a deep, warm resonant sound, clear lacquer finish adds a subtle warmth overall. Ideal for both symphonic and solo performance. www.carltonmusic.com