ARC-8028MB is a OEM Mounting Bracket for user to leverage the ATX I/O Shield position as ARC-8028 box I/O port. You can use ARC-8028MB to fit ARC-8028 box I/O port in the standard ATX I/O-Slot found in a Rackmount Chassis. An ATX I/O Shield is a small metal plate located at the back of each rackmount chassis that provide openings for different I/O ports of a motherboard.