The rear I/O shield specifications are comprehensive for an OEM product:
Can you find a with a 6- or 9-digit number starting with AA on the board? 3rd-gen-core-desktop-vol-1-datasheet.pdf - Intel
The Intel Desktop Board D21-B6-E1/E2 is a reliable and feature-rich motherboard designed for Intel's 2nd and 3rd generation Core processors. With its Micro-ATX form factor, it's suitable for a wide range of desktop systems, from home users to businesses and enterprises. The E1 and E2 variants offer slightly different feature sets, catering to specific needs and use cases.
