ESTeem Wireless Modems, Inc

Any device whose MAC address begins with 00:04:3F has a network interface built by ESTeem Wireless Modems, Inc. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

00:04:3F

Organization

ESTeem Wireless Modems, Inc

Address

415 N. Quay St., Suite 4 Kennewick WA US 99336

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.