What this means
The IEEE assigned the MA-S block 70B3D5A30 to SHEN ZHEN HUAWANG 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 70:B3:D5:A3:0, it is SHEN ZHEN HUAWANG TECHNOLOGY CO; LTD hardware.