Monel Rotors Bb/F 4 Keys Double French Horn w/Case & Mouthpiece-Nickel Plated Finish Flawless Nickel Plated Finish Key of Bb/F, Bore Size : .469 inch, Bell Dia : 12.244inch Easy to Carry Detachable Bell, Balanced Weight Design Durable Light Weight ABS Case 4 Durable Monel Smooth Rotors, Fast and Smooth Rotary response