What this means
The IEEE assigned the MA-S block 8C1F64D9D to MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD.. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting 8C:1F:64:D9:D, it is MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD. hardware.