The MB448 Series is a 2.5" Duo internal & external USB hard drive removable rack that fits into a standard 3.5" drive bay slot usually for floppy disk device if your standard 5.25" drive bays are overwhelmed by CD, DVD or so devices that you are unable to fit other storage drive devices into your system. Conforming to the idea of a 5.25" removable drive rack, the slim device keeps security, exchangeability, expandability, manageability available without sacrificing the needs of your 5.25" drive bays. Moreover, this series has options that are capable to be used both internally & externally. This means instant swap of cartridge transforming into a portable storage drive in seconds! The series is also excellent for smaller diverse system solution providers whom are confined due to size limitations when integrating removable storage drives.