Iconic Omega Megasonic Chronometer 720Hz watch Cal 1220 ref 198.0065, working. Innovative design and highly collectible. Some info suggests only 50,000 of these interesting timepieces were manufactured. Fair condition for age. May benefit from new crown as some plate wear. Looks like it needs new caseback gasket. As with all vintage watches, service may be required o ensure best future performance longevity and accuracy of movement.