100% Model Identification for Apple Devices - Here's How!
1. Open System Information
Click on the Apple logo 
in the top left corner and select “About This Mac” from the drop-down menu.
in the top left corner and select “About This Mac” from the drop-down menu. 
2. Open System Report
A system overview will appear. Here, you’ll find basic information about your device. For example, it could be an iMac Early 2008 with a Core 2 Duo processor running at 2.8GHz. However, this information alone is not sufficient to precisely identify your system.
Depending on your operating system version, the views may differ:
from OS X El Capitan – Version 10.x
Click on the “System Report…” button.
for older versions before El Capitan – Version 10.x
Click on “More Info…“.
Click here on the button “System Report…“
3. Apple Model Identification
In the System Report, you will now find numerous details about your system. Since Apple device names are often vague and can lead to confusion, we strongly recommend looking for the Model Identifier of your device. This is the correct designation of your model, which will help you find the right memory.
4. Find memory for your Apple model
Copy the value from the “Model Identifier” field in your System Report and simply enter it into the full-text search on phs-memory.com in the header section of the page. You can be sure that the found memory is also 100% compatible with your Apple device.