If you are in the Mac tech support business you inevitably end up using a very cool app called Mactracker. There is no way a person can remember all the OS parameters and other specs for a particular Mac machine. So, you can get general info off the Apple GSX (Global Service Exchange) or you can get more detailed info off Mactracker.
Mactracker is Donationware. It is free, but if you find it useful (and you will!) please donate. This is an invaluable application. When you open Mactracker you will see this screen:
The left hand column shows pretty much all macs from forever. If you look closely you will see it has a Timeline up top for when Apple products were released and a Devices section down below listing all Apple devices over the years. If you wish to find out what models Apple has currently just click on Current Models at the very top of the left sidebar.
The above screenshot shows the specs for my Late 2012 iMac. The main General tab gives you a good overview. There are times when you need to know the “Model Identifier” or the “Model Number” and other esoteric information. Out of the tabs across the top of the screen I use General and Memory and Graphics the most.
If you work on Macs or just for your own information about your own Macs I encourage you to download Mactacker. If you decide it is useful please make a donation and support good software development.