Used Walter Monnig single Bb horn with A muting valve and F extension. This is not a typical single Bb. The horn has a large bell throat which gives it a nice big sound, still with the upper register advantages of a single Bb. The F extension intonation is so-so, but fills in notes that cannot be used on a single Bb. The extension operates off the muting valve and is activated with a change rotor which can be set to use the extension or not. It is un-lacquered brass, in excellent condition. Comes with a hard plastic case.