勞力士，小巧及極罕有，不銹鋼腕錶，配單按鈕計時功能及雙色錶盤，型號3462，約1939年製

The Rolex Centregraph, together with its sister model Zerograph, is believed to be the very first "Oyster" chronograph wristwatch. Its standard 10 ½ lines movement was upgraded with a return-to-zero or fly-back mechanism. The timing of a single event was possible by rotating the bezel to match the minute hand and returning the seconds hand to zero by means of the pusher. The elapsed time could then be measured on the bezel.

Sold to the Canadian market, the Centregraph model is believed to have been supplied to Canadian soldiers departing for active service in Europe during WWII. The inside case back of the present watch is stamped with a parachute and the letters RM, probably relating to the Royal Marines.

To the best of our knowledge, no more than 50 examples of the Centregraph were produced, and available exclusively in stainless steel.