What this means
The IEEE assigned the MA-S block 8C1F6463F to PREO INDUSTRIES FAR EAST 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:64:63:F, it is PREO INDUSTRIES FAR EAST LTD hardware.