What this means
The IEEE assigned the MA-M block 18FDCB0 to Shenzhen Rui jiali Electronic Technology Co. 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 18:FD:CB:0, it is Shenzhen Rui jiali Electronic Technology Co. Ltd. hardware.