I bought it on ebay, it's Python leather, with a lot of Breitling engravings. Frankly speaking I don't believe it is really a genuine Breitling strap. But it looks great!
It is a M. Johanssen Modell Cales. Sometimes you can find one on ebay. Have a look:
http://www.ebay.de/itm/GEBRAUCHTE-M-JOHANSSON-HANDAUFZUG-SKELETT-UHR-G-CalesSS-/331351349128