FelixNZ.
You won't need an adapter. You could simply connect it with the SATA cables (power and data) and you should be OK. However since the drive is smaller (2.5" instead of 3.5" form factor which is the size of a desktop drive), unless you have 2.5" drive bays in your case you might have to get a mounting kit/bracket in order to fit it in the larger drive bay.
Hope that helps. Please let me know if you have any questions.
Boogieman_WD