Search for specific file types

Here's a simple trick you all must know when you want to search for a specific file type in Google.
Here's what you need to do.
I had to present a presentation on Stars and had to make it on PowerPoint.
So as u know PowerPoint presentation have an extension i.e. ppt (or pptx).
So here's what you should type in the search box in Google.

Space filetype:ppt

Its that simple. And the coolest thing it shows the link to directly download the file. So the download would start if you click on any search results.
Cool isn't it.