Regarded as the most expensive series model so far is the Mystery Masterpiece, a cooperation with Van Cleef & Arpels, of which there are three examples each in red, blue and green; the price stated was around 558,000 euros. The piece is set with numerous diamonds and coloured precious stones. Upwards, however, individual pieces or later editions are basically open, so this price does not represent a final upper limit. Further details can be found on the official Montblanc page for the model.