Dial case and movement signed. DIM. 25 x 41 mm. This extremely rare Sporting Prince was the answer by ROLEX to provide a protective case for increased protection. Made also in 9K and in 18k pink gold production was extremely limited and to the best of our knowledge only 6 examples have appeared at auction in the last 20 years. The case of this watch was designed by HANS WILSDORF himself and patented in Switzerland on December 26 1929.