WindowMaster A/S

Any device whose MAC address begins with F4:B3:81 has a network interface built by WindowMaster A/S. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address.

OUI prefix

F4:B3:81

Organization

WindowMaster A/S

Address

Skelstedet 13 Vedbaek DK 2950

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.