Omega Seamaster Aqua Terra 231.10.42.21.02.001 42 mm Silver Dial

If the Aqua Terra is 42 mm and the code is 231.10.42.21.02.001, you are looking at a discontinued Seamaster Aqua Terra 150M. Diameter is the only specification attached to this reference, so the number has to do the identifying work. It is not the 41.5 mm 231.10.42.21.02.002, and it is not a current 220-series Aqua Terra.

Six Saudi listings currently use this code. The dangerous neighbour is 231.10.42.21.02.002, a different Aqua Terra whose number differs by a single digit. 231.10.42.21.03.001 and 231.10.39.21.01.001 sit in the same family at other sizes. Read 231.10.42.21.02.001 in full on every listing before you compare the six.