Can do both
Fits into a 5.25" bay and offers space for one 2.5" and one 3.5" drive. Both drives have their own connection and work independetly of each other. A data transfer rate of up to 6 Gbit/s can be achieved.
Safety is taken care of
Both hard disk slots can be locked and the installation or exchange of drives is fast and uncomplicated due to the trayless design.
Rest
Depending on whether the drives are to be used or not, the two hard disks can be switched on or off at the same time without making any major changes to the hardware.