The 88H Series features a .547-inch primary bore combined with a .562-inch bore standard wrap F attachment plus an 8.5-inch bell that offers outstanding clarity and projection. Conn 88H Symphony Series F Attachment Trombone Features: * Key: Bb / F * Bore: .547-inch * Leadpipe: Fixed * Leadpipe Material: Yellow Brass * Bell: 8.5-inch * Bell Material: Rose Brass, Yellow Brass, Sterling Silver * Handslide: Standard Weight * Handslide Material: Rose Brass * Handslide Crook Material: Nickel Silver * F Attachment Wrap: Standard * F Attachment Valve: Standard Rotor * Features: .562-inch Bore F Attachment; Adjustable Thumb Lever * Case: Yes * Mouthpiece: Conn 5G * Mouthpiece Shank: Large * Finish: Lacquer