Amati F/B M500 Maestro

I bought this clarinet second-hand from Melbourne four years ago. It was made in Czechoslovakia. It is a Bb Clarinet with an extra key, I think either an F or Eb at the bottom near the bell on the lower section. It has two sets of mouthpieces and two sets of barrels. It is made out of real wood and thus needs to be wiped with wood oil every so often so that it does not dry up.