3.5" To 5.25" Hard Drive Bay Metal Mounting Bracket Adapter Kit Dock Holder 3.5" To 5.25" Hard Drive Bay Metal Mounting Bracket Adapter Kit Dock Holder Material:mental Fit any 3.5" HDD into your existing 5.25'' Drive Bay Work with 3.5" internal card reader or USB hubs Maximize the internal space of your computer case for efficient usage