What this means
The IEEE assigned the MA-L block 5033F0 to YICHEN (SHENZHEN) 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 50:33:F0, it is YICHEN (SHENZHEN) TECHNOLOGY CO.LTD hardware.