AN OMEGA 18K YELLOW GOLD MEGASONIC OPEN-FACE POCKET WATCH.

Model: Megasonic 720 Hz De Ville
Date: Late 1970s
Movement: Signed, 18 jewels, Cal. 1120, No. 3492XXXX
Dial: Signed, champagne, gilt applied hour batons, black outer minute division, gilt and black sword hands, gilt centre seconds hand, date aperture at the three o'clock position with a white calendar disk and black Arabic numerals
Case: Signed, 18k yellow gold, open-face pocket watch, No. 198XXXX
Size: 47.8mm
Weight: Approx. 81.2g.

Designed by Max Hetzel, the inventor of the Bulova Accutron watch, the Omega Caliber 1220 Megasonic 720Hz was launched in 1973,featuring an asymmetric tuning fork resonating at 720Hz instead of the normal 300Hz. The watch is run by an Omega micromotor, which consists of an oil-filled and sealed box with a transparent cover - inside this box, a wheel mounted on four rubies bounces off two opposing ruby springs every time the tuning fork vibrates. A further unique characteristic is the absence of a physical connection between this vibrating tuning fork and the movement, as magnetic gears drive the movement, but the gears have no teeth, instead using magnets to generate movement.

Dimensions: 47.8mm.