The YEP-321 is an excellent choice for pro doublers or serious amateurs. It features a strong warm tone, and is easy to play, with accurate intonation. * In Bb * Valves: 4 top action * Bell: 280mm (11) * Bore: 14.5-15.5mm (0.571-.610) * Finish: Clear lacquer * Silver-plate YEP-321S * Mouthpiece: 48