Which company owns MAC address prefix E4:81:B3?

MAC address prefix E4:81:B3 is registered to Shenzhen ACT Industrial Co.,Ltd. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with E4:81:B3 has a network interface built by Shenzhen ACT Industrial Co.,Ltd..

What is the OUI E4:81:B3?

E4:81:B3 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Shenzhen ACT Industrial Co.,Ltd.. It covers every address from E4:81:B3:00:00:00 to E4:81:B3:FF:FF:FF, or 16,777,216 addresses in total. It is also written E4-81-B3.

How do I find the manufacturer of a MAC address?

Take the first three octets of the address — in E4:81:B3:00:00:00 that is E4:81:B3 — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.

Where is Shenzhen ACT Industrial Co.,Ltd. located?

Shenzhen ACT Industrial Co.,Ltd. is listed at NO.5 B/D,BEISHAN INDUSTRIAL PARK,BEISHAN R/D, Shenzhen Guangdong CN 518083 in the IEEE OUI registry entry for E4:81:B3. This is the address the organization registered with the IEEE, which may differ from its current operating address.

Shenzhen ACT Industrial Co.,Ltd.

MAC address prefix E4:81:B3 is registered to Shenzhen ACT Industrial Co.,Ltd. in the IEEE OUI registry. Any device whose MAC address begins with E4:81:B3 has a network interface built by Shenzhen ACT Industrial Co.,Ltd.. This prefix (the OUI, or Organizationally Unique Identifier) is assigned by the IEEE and is the first three octets of the address — it covers every MAC from E4:81:B3:00:00:00 to E4:81:B3:FF:FF:FF.

OUI prefix: E4:81:B3
Hyphen form: E4-81-B3
MAC range: E4:81:B3:00:00:00 – E4:81:B3:FF:FF:FF
Addresses in block: 16,777,216
Organization: Shenzhen ACT Industrial Co.,Ltd.
Address: NO.5 B/D,BEISHAN INDUSTRIAL PARK,BEISHAN R/D, Shenzhen Guangdong CN 518083
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.

Assignment history (2)

The IEEE registry publishes current state only — this is the change record we've kept since we started tracking it daily.

2016-07-29Assigned to "Shenzhen ACT Industrial Co.,Ltd."
archived source →
2026-07-17Assigned to "Shenzhen ACT Industrial Co.,Ltd."

Nearby in the registry

The prefixes assigned immediately before and after E4:81:B3:

FAQ

Which company owns MAC address prefix E4:81:B3?: MAC address prefix E4:81:B3 is registered to Shenzhen ACT Industrial Co.,Ltd. in the IEEE Organizationally Unique Identifier (OUI) registry. Any device whose MAC address begins with E4:81:B3 has a network interface built by Shenzhen ACT Industrial Co.,Ltd..
What is the OUI E4:81:B3?: E4:81:B3 is an Organizationally Unique Identifier — the first three octets (24 bits) of a MAC address, assigned by the IEEE to Shenzhen ACT Industrial Co.,Ltd.. It covers every address from E4:81:B3:00:00:00 to E4:81:B3:FF:FF:FF, or 16,777,216 addresses in total. It is also written E4-81-B3.
How do I find the manufacturer of a MAC address?: Take the first three octets of the address — in E4:81:B3:00:00:00 that is E4:81:B3 — and look that prefix up in the IEEE OUI registry. If the second-lowest bit of the first octet is set, the address is locally administered (a randomized or private MAC), which belongs to no manufacturer and will not resolve; modern phones and laptops use these by default on each network.
Where is Shenzhen ACT Industrial Co.,Ltd. located?: Shenzhen ACT Industrial Co.,Ltd. is listed at NO.5 B/D,BEISHAN INDUSTRIAL PARK,BEISHAN R/D, Shenzhen Guangdong CN 518083 in the IEEE OUI registry entry for E4:81:B3. This is the address the organization registered with the IEEE, which may differ from its current operating address.