What kind of external hard disk can I connect to Ariva HDcombo?

Image Ariva HDcombo support most of external hard disks. 3,5'' hard disks with sepparate power supply should work. Some 2,5'' hard disks powered from USB port (for example WD My Passport Essential) also should work.
There should be only one primary FAT32 partition on the disk.
HDD only up to 750 GB are supported.