Because so many people not requesting any I/O shield.
Motherboard ATX IO Shield Backplate Non-Standard OEM Layout Unique Rear Ports
Motherboard ATX IO Shield Backplate 3 Horizontal Audio Ports USB Ports Far Right
Motherboard ATX IO Shield Backplate with DVI Port
Motherboard ATX IO Shield Backplate 6 Audio Ports Parallel LAN No SPDIF Port
Motherboard ATX IO Shield Backplate 3 Vertical Audio Port 4 USB - Type 1
Motherboard ATX IO Shield Backplate Gap then 3 Vertical Audio Ports Far Right
