Key: Bb Pitch: A445 Bore: 11.89 mm (.468") Mouthpipe: .306 venturi, yellow brass Lever action: Noiseless string action, short stroke with stainless steel springs Valve rotors: Tapered hand-lapped brass Bearing plates: Tapered brass Material: Brass branches, bows, crooks and connecting ferrules are brass Slides: Both inside and outside are lacquered brass Bell: 12.25" diameter small-throated yellow brass