Stainless steel Omega Constellation chronometer dated by serial number to 1966 with original silver dial with even patina and original hands in nice condition. The The automatic 564 movement within keeps excellent time and it has a quick set date feature (date changes when crown is pulled out). The case, reference number 168.017, has embossed observatory logo on back which signifies its chronometer rating. Photos are magnified and show details not seen by naked eye, the case measures 34 mm across (not including crown) x 40 mm lug to lug.