Brand New Authentic Omega Constellation Automatic Chronometer 38mm Men's Watch Model 123.10.38.21.01.001. Steel case with Steel watch band. Black dial. Automatic Self Winding movement. Scratch Resistant Sapphire crystal. Case size: 38mm. Transparent case back. 100 Meters/330 Feet water resistant. 5 year WatchMaxx warranty. Also known as model: 12310382101001, 123-10-38-21-01-001, 012310382101001.