The IODD 2531 is a 2.5″ hard drive enclosure with an interesting twist–it can also emulate a CD-ROM.
The software on the enclosure will let the end user switch to CD-ROM emulation mode. From there, the user can select a specific ISO stored on the hard drive and then boot any computer device that supports CD-ROM boot.
So rather than having to carry multiple USB devices or CDs that have OS installs images, a user could store them all on this device and switch quickly to the necessary ISO.
Very clever.