勞力士，18K金自動上弦腕錶，配中心秒針、日曆顯示、「雷鳥」錶圈及乳白色錶盤，”Turno-O-Graph”，型號6309

Datejust Turn-O-Graph reference 6309 was adopted as the official watch by the famed American Air Force Thunderbird acrobatic team. The graduated rotating bezel of the watch is highly recognizable due to its part engine-turned and part engraved design. It served as a memo or could be used in the same way as a chronograph to measure elapsed time. This type of bezel is known as "Thunderbird" among collectors due to its immediate association with the U.S. Thunderbird squadron. The name thunderbird comes from the mythology of certain North American indigenous people and is considered a supernatural bird of power and strength.

Reference 6309 immediately followed in the footsteps of reference 6202, the latter was introduced to the market in 1954 and had a revolving bezel with a triangle at the zero position. Only two years later, both references were followed by reference 6609, which was also adorned with the collectable "Thunderbird" bezel.

According to research, the present watch belonged to a Colonel Don Ferris, who was a US Air Force Commander in the 1950s and team member of the Thunderbirds. The watch is in overall excellent condition, the slight oxidation in places being witness to the fact that the watch has not been subject to much polishing, if at all, and a crisp hallmark on the underside of the upper right lug. The period cream dial and beautiful Thunderbird bezel give the watch a very bright and charming character. The fact that the watch belonged to an actual member of the skillful Thunderbirds team only enhances its overall appeal.