Aurora R8, add a 3.5" HDD?

I just received.  I ordered it with a single SATA 1.0 gig HD.  Is this drive a 2.5" or a 3.5"?  Can I add a 3.5" from an old computer for backup only.  I did not want to open up the case until I know what I have is compatible and there is room.  I have not seen this answered.  The 3.5" to add is 7200 rm and .5 gig.

Thanks to all,