Not sure if this is the right power adapter for your Mac?
Knowing which specific Mac model you have is important. If you are running OS X Lion (10.7) or later go to the “” menu at the top left of your screen, choose “About this Mac” then click the “More Info...” button. Your Mac model and generation will be displayed.
If you are running an earlier version of OS X, you can enter your serial number here to find out which model you have.