ICY BOX IB-174SSK-U 13.3 cm (5.25") Storage drive tray Black

Can do both
Fits into a 5.25" bay and offers space for one 2.5" and one 3.5" SATA HDD. Both HDDs 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. The trayless design and hotSwap make the exchange of HDDs faster and more convenient.

Rest
Depending on whether the HDDs 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.