This is an exceptional Yamaha 639 made in late 70s or early 80s. It was designed in collaboration with Schilke and is a clone of the B3. .463” large bore. 4 7/8” gold brass bell. I have a 738 that I prefer to this one, so I’m willing to let it go to someone who will play it!  Despite the large bore, it blows very focused and bright. It is an excellent lead/commercial horn. Comes with a case in great shape and a generic 7C mouthpiece. No dents. Minor lacquer wear. All valves and slides move freely.