Winner
Updated October 2026
Data from Amazon and official Smlight and Sonoff sites.
2026 verdict
The Smlight SLZB-MR5U takes this one on flexibility: it is a network coordinator that runs Zigbee and Thread at the same time, where the Sonoff Dongle Lite MG21 is a USB stick doing one at a time.
Built on Silicon Labs EFR32MG24 radios with two +5 dBi external antennas, the MR5U connects over Ethernet with PoE, Wi-Fi or USB, works as a Zigbee coordinator, router and Thread border router, and doubles as a Bluetooth proxy. The Sonoff Dongle Lite MG21 is the far cheaper option, an EFR32MG21 stick with +20 dBm of transmit power that can also be flashed for Thread, and it has a long list of owner reports behind it while the MR5U is too new to have many. Pick the Smlight SLZB-MR5U for a central PoE box serving Zigbee, Thread and Bluetooth together, and the Sonoff Dongle Lite MG21 for a budget Zigbee network plugged into the Home Assistant host.
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| Feature | Smlight SLZB-MR5U | Sonoff Dongle Lite MG21 | Winner |
|---|---|---|---|
| Price | $119.99 | $24.90 | Sonoff Dongle Lite MG21 |
| Rating | 5.0 | 4.5 | Smlight SLZB-MR5U |
| Power | USB, PoE | USB | Smlight SLZB-MR5U |
| Connectivity | USB, Ethernet, 2.4 GHz WiFi | USB | Smlight SLZB-MR5U |
| Antenna Gain | +5dB | +2dBi | Smlight SLZB-MR5U |
| Dual Network | YES | NO | Smlight SLZB-MR5U |
| Bluetooth Proxy | YES | NO | Smlight SLZB-MR5U |
| Zigbee Chip Model | EFR32MG24 | EFR32MG21 | Different strengths |
| Warranty | 1 year | 1 year | Tie |
| Zigbee Router | YES | YES | Tie |
| Z-Wave Controller | NO | NO | Tie |
| Thread Border Router | YES | YES | Tie |
What the differences mean
Zigbee and Thread together
The Smlight SLZB-MR5U runs Zigbee and Thread simultaneously. The Sonoff Dongle Lite MG21 ships for Zigbee and has to be flashed to become a Thread radio, after which it does Thread instead of Zigbee.
How it connects
The Smlight SLZB-MR5U connects over Ethernet with PoE, Wi-Fi or USB, so it can sit centrally in the home. The Sonoff Dongle Lite MG21 is USB only and plugs into the Home Assistant host, moved a little with its extension cable.
Bluetooth proxy
The Smlight SLZB-MR5U also relays Bluetooth sensors to Home Assistant. The Sonoff Dongle Lite MG21 has no Bluetooth proxy.
Track record
The Sonoff Dongle Lite MG21 has plenty of owner reports behind it. The Smlight SLZB-MR5U is a recent model with little independent experience published so far, so its strengths are on paper for now.
Which one to buy if
- you run Zigbee devices and Matter over Thread devices
The Smlight SLZB-MR5U serves both networks at once instead of making you choose.
- you are starting a small Zigbee network on a budget
The Sonoff Dongle Lite MG21 is far cheaper and owners find it nearly plug-and-play in Home Assistant.
- your server sits far from the devices
The Smlight SLZB-MR5U can be placed centrally on a PoE cable.
- you want a spare stick to extend the mesh as a router
Owners run extra Sonoff Dongle Lite MG21 sticks as Zigbee routers around the house.
Winner
$119.99
- + Rating: 5.0
- + Power: USB, PoE
- + Connectivity: USB, Ethernet, 2.4 GHz WiFi
- - Price: $119.99 vs $24.90
- + Price: $24.90
- - Rating: 4.5 vs 5.0
- - Power: USB vs USB, PoE
What owners say
Sonoff Dongle Lite MG21 owners describe a cheap, compact way into a local smart home that is nearly plug-and-play in Home Assistant through Zigbee2MQTT or ZHA, with sixty-plus devices running reliably and range that reaches through three walls or to the edge of the yard. They are glad the USB extension cable comes in the box to get the stick away from USB 3 interference, and like using the same stick as coordinator, router or Thread radio, one owner running three around the house. Their complaints are about Thread: flashing it over took more effort than expected for some, and a firmware update once broke OpenHAB support for one user.
Price history compared
Every price change of both, in the same store, so the gap between the two lines is what one costs more than the other.
- Smlight SLZB-MR5U
- Sonoff Dongle Lite MG21
Loading price history...
Frequently Asked Questions
Which is better overall: Smlight SLZB-MR5U or Sonoff Dongle Lite MG21?
The Smlight SLZB-MR5U, because it runs Zigbee and Thread at the same time, connects over Ethernet, PoE, Wi-Fi or USB and adds a Bluetooth proxy. The Sonoff Dongle Lite MG21 is the budget USB alternative for a Zigbee network.
Can the Smlight SLZB-MR5U and the Sonoff Dongle Lite MG21 run Zigbee and Thread together?
Only the Smlight SLZB-MR5U, which supports dual-network operation. The Sonoff Dongle Lite MG21 can be flashed for Thread, but then runs Thread instead of Zigbee, not both.
What is the biggest difference between the Smlight SLZB-MR5U and the Sonoff Dongle Lite MG21?
Scope. The Smlight SLZB-MR5U is a PoE network gateway for Zigbee, Thread and Bluetooth at once, while the Sonoff Dongle Lite MG21 is a simple USB stick for one protocol at a time.
Do the Smlight SLZB-MR5U and the Sonoff Dongle Lite MG21 work with Home Assistant?
Yes. Both work with Home Assistant and Zigbee2MQTT. Owners of the Sonoff Dongle Lite MG21 also use it with ZHA, Node-RED and OpenHAB, while the Smlight SLZB-MR5U is too new for much owner feedback.
Who should buy the Smlight SLZB-MR5U?
Home Assistant users with a PoE switch who want one central box to run Zigbee and Thread together and relay Bluetooth sensors, and who do not need a Texas Instruments radio.
Who should buy the Sonoff Dongle Lite MG21?
First-time Home Assistant builders and budget buyers who want a reliable Zigbee USB coordinator, or cheap extra sticks to use as routers.
Full comparison table
Compare all 36 Dongles side by side
You are looking at two of them. The full table lines up all Dongles in the catalog with the same specs, so you can filter by what you need and sort by price or rating.
- 36 Dongles
- 32 specs compared
- 29 filters
SmlightSLZB-MRW10
$100.00
SmlightSLZB-06 U
$72.99
SmlightSLZB-MR3
€158.13- Smlight
SLZB-MR5U
$119.99 
SmlightSLZB-07
$34.99
SmlightSLZB-MR1U
$102.99
SmlightSLZB-07p7
$36.99
SonoffZBDongle-E
$24.90
SonoffDongle Plus MG24
$35.90
Nabu CasaHome Assistant Connect ZBT-2
$65.00
SonoffZBDongle-P
16% OFF$39.99$33.47
ZoozZ-Wave Long Range Stick
$39.95
Nabu CasaHome Assistant Connect ZWA-2
$79.00
SonoffDongle-PZG23
$39.90
SmlightSLZB-06M
$72.99
SonoffDongle Plus PP10
$35.90
SmlightSLZB-06p7U
$78.99
SmlightSLZB-MR2
€111.97- Sonoff
Dongle Lite MG21
$24.90 
AeotecZ-Stick 7
$39.99
DonglesSmlightSLZB-06 MG24
4.5(6)$82.99
DonglesSmlightSLZB-06 MG26
3.4(7)$84.99- DonglesSmlight
SLZB-06 U
5.0(5)$72.99 
DonglesSmlightSLZB-06
4.2(182)$72.99- DonglesSmlight
SLZB-06M
4.6(111)$72.99 
DonglesSmlightSLZB-06P10
4.4(11)$85.99
DonglesSmlightSLZB-06p7
4.4(11)$79.99- DonglesSmlight
SLZB-06p7U
4.6(33)$78.99 
DonglesSmlightSLZB-07 MG24
3.3(5)$45.99
DonglesSmlightSLZB-07 MG26
4.5(86)- DonglesSmlight
SLZB-07
4.9(20)$34.99 
DonglesSmlightSLZB-07P10
3.0(1)$48.99- DonglesSmlight
SLZB-07p7
4.8(8)$36.99 
DonglesSmlightSLZB-MR1
4.4(11)$103.99- DonglesSmlight
SLZB-MR1U
4.8(16)$102.99 - DonglesSmlight
SLZB-MR2
4.6(8)€111.97 - DonglesSmlight
SLZB-MR3
5.0(1)€158.13 
DonglesSmlightSLZB-MR4
4.0(5)$130.00- DonglesSmlight
SLZB-MR5U
5.0(1)$119.99 - DonglesSmlight
SLZB-MRW10
5.0(11)$100.00
Air Quality MonitorsSonoffSAWF-07P Air Quality Monitor
3.7(193)$39.90
Air Quality MonitorsSonoffSAWF-08P Air Quality Monitor
4.3(169)$49.90
CamerasSonoffCAM GlassView
4.4(30)$34.90
CamerasSonoffCam Outdoor DUO
$79.90
CamerasSonoffCam Slim Gen2
4.4(176)$19.90
CamerasSonoffGK-200MP2-B
4.0(149)30% OFF$9.99$6.99
DisplaysSonoffNSPanel Pro Gen2
3.4(11)€149.90
DisplaysSonoffNSPanel Pro
4.1(75)$129.90- DonglesSonoff
Dongle Lite MG21
4.5(452)$24.90 
DonglesSonoffDongle Max
4.3(603)18% OFF
€38.99€32.13- DonglesSonoff
Dongle Plus MG24
4.7(690)$35.90 - DonglesSonoff
Dongle Plus PP10
4.6(99)$35.90 - DonglesSonoff
Dongle-PZG23
4.6(175)$39.90 
DonglesSonoffZ-Wave 800 PoE Dongle Max
4.5(26)$44.90- DonglesSonoff
ZBDongle-E
4.7(3,743)$24.90 - DonglesSonoff
ZBDongle-P
4.6(5,678)16% OFF$39.99$33.47 
Door & Window SensorsSonoffDW2-WIFI
3.8(1,058)$12.23
Door & Window SensorsSonoffSNZB-04 ZigBee Wireless Door/Window Sensor
3.7(101)$17.99
Door & Window SensorsSonoffSNZB-04P ZigBee Door/Window Sensor
4.0(13)$18.99
Door & Window SensorsSonoffSenseGuard DW Gen2
4.4(203)£35.00