Used King 3B ‘Concert’ F-attachment trombone. The 3B, with its F-attachment, is a great trombone with a full warm tone. The bore on the 3B is .508″ and it has an 8″ bell. This particular horn is in excellent condition with little lacquer wear, a smooth slide and only a couple of very minor dents on the crook. Included with the price are two Benge 6 1/2 AL-S mouthpieces, a Benge 12C mouthpiece, a Bach 5G mouthpiece, a Connstellation 5C-N gold plated mouthpiece and the original hard shell case.