This is an authentic Omega vintage grey watch hang tag that came with a Seamaster 2850.50.02 watch. Your tag measures 3cm by 2cm. The writing on the back reads 28505002, 54618661, 1438.
28505002 is the model number, 54618661 is the serial number and 1438 is the movement number.
I have given you photos of your watch tag from every angle. Please use them to add to this description.
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