StarTech.com 3.5" to 5.25" Front Bay Adapter - Mount 3.5" HDD in 5.25" Bay - Hard Drive Mounting Bracket w/ Mounting Screws (BRACKETFDBK) - storage bay adapter

Install a 3.5in hard drive into a single 5.25in front bay. This plastic, floppy-drive adapter bracket lets you install a 3.5in floppy drive into a 5.25in bay.
A simple solution that lets you position a 3.5in floppy drive in a computer case as needed (without being confined to the 3.5in floppy bay determined by the case layout), the floppy drive adapter bracket features an attractive open-faced black bezel that provides a snug, secured fit for installed drives.