Produced in stainless steel only in fewer than 50 examples.The Centregraphas well as the Zerograph is a very high-precision instrument able to calculate intermediary consecutive times. It is forexample useful when necessary in one single operation - to stop go back to zero and restart the second hand forsports events car motorbike or bicycle racing or even to calculate the production times in manufacturing.A similar watch is published in Rolex Collecting Wristwatches by OSVALDO PATRIZZI GUIDO MONDANI Editore