A-Team Technology Ltd.

Any device whose MAC address begins with 00:21:3F has a network interface built by A-Team Technology Ltd.. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

00:21:3F

Organization

A-Team Technology Ltd.

Address

Rm. 1608, 16/F., Metropole Square, New Territories, HK

Source

IEEE OUI registry

Have a full MAC address? Look it up— we'll also tell you if it's a randomized (private) address rather than a real manufacturer prefix.