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【High-Accuracy Sensing】Measures temperature with ±0.2°C (±0.4°F) accuracy and humidity with ±2%RH accuracy. Data refreshes every 5 seconds for reliable real-time monitoring.
【Dew Point & VPD Monitoring】Go beyond basic temperature and humidity monitoring with real-time Dew Point and Vapor Pressure Deficit (VPD) analysis. Detect condensation risks early, help prevent mold growth on walls, furniture, and valuables, and maintain ideal transpiration conditions for healthier plants.
【Slim Design for Small Spaces】Only 27.8 mm wide and 20 mm thick. Supports both hanging and adhesive mounting for flexible installation in guitar cases, cigar humidors, jewelry cabinets, wine racks, and other tight spaces.
【Long Battery Life】Powered by two standard AAA batteries, designed for easy replacement and no specialized tools required, delivering up to 2 years of battery life for long-lasting, maintenance-free operation.
【6-Month Data History】View temperature, humidity, dew point, and VPD trends anytime in the app. Access up to six months of historical data to monitor long-term environmental changes.
Technical details, troubleshooting or setup tips? Access the SNZB-02B knowledge center for all the info you need.
Compact Design Fits Anywhere
Compact and exquisite design allows easy placement even in small spaces; equipped with a lanyard, it can be hung freely anywhere.


Also Fits Perfectly In
Hidden Threats You Can Now Monitor
Supports dew point and VPD monitoring, turning invisible environmental threats into visible data.
Say goodbye to moldy walls—start by monitoring the dew point.
Stop guessing, start measuring—VPD is the grower's true compass
No More "Low Battery" Anxiety
Powered by 2 standard AAA batteries, with a battery life of up to 2 years — no wiring, no charging, just quietly guarding.
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**The battery life data is a theoretical value, obtained from SONOFF's internal laboratory under a specific test environment.
Actual use may vary slightly due to product differences, firmware software versions, operating conditions, and environmental factors. Please refer to the actual use.
Intelligent Sensing. Automatic Control
You can freely set your comfort range and customize smart scenes. When the environment exceeds the preset range, you’ll receive an instant alert, and appliances like electric fan and dehumidifier will automatically turn on.
Let The Room Decide, Not The Radiator
Place the sensor where you live. It detects the real room temperature and tells your smart valve when to stop — so you stay comfortable, not just the radiator.
It Remembers The Last 6 Months
Enjoy 6 months of free cloud storage and track temperature and humidity changes at any time. With data export support,
every analysis is backed by solid evidence.
Hands-Free Voice Commands
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*Note: This function requires adding the device to the eWeLink app and syncing it to third-party platforms via cloud-to-cloud integration;
This process does not involve direct connection to the third-party gateway.
Works with Apple Home Via Matter Bridge
All solutions integrate SONOFF Zigbee devices into your Apple ecosystem via Matter Bridge, enabling seamless interconnected device control.
Learn More about ZBBridge-U | Learn More about eWeLink CUBE
Easily Integrates with Open-Source Platforms
Built on the Zigbee 3.0 standard, this device effortlessly connects with a wide range of third-party platforms.
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*Currently, using the AirGuard TH Lite with ZHA requires the script. For detailed instructions, please refer to: https://help.sonoff.tech/docs/SNZB02B
Zigbee Hub Compatibility
Product Comparison
Specifications
Specs & User Manual
SNZB-02B (AirGuard TH Lite) is a Zigbee temperature and humidity sensor designed for precise environmental monitoring. It measures temperature and humidity with high accuracy, while automatically calculating dew point and VPD for deeper environmental insights. Data refreshes every 5 seconds for reliable real-time monitoring. Its compact design fits easily into small spaces and supports both hanging and adhesive mounting. Powered by two standard AAA batteries, it offers convenient tool-free replacement. The app provides real-time readings and up to 6 months of historical data trends.
User Manual (PDF)AirGuard TH Lite
AirGuard Series
Zigbee Temperature Humidity Sensor
SNZB-02B
TLSR8656
3.0V ⎓ (2×1.5V batteries)
LR03 AAA
Zigbee 3.0 (IEEE 802.15.4)
43.0g (including batteries)
White
66.3×27.8×20mm
PC
Indoor
-20°C ~ 60°C
5-95%RH (non-condensing)
±0.2°C/±0.4°F
±2% RH
CE/FCC/RoHS
FAQ
1. How can I view the Dew Point and VPD values?
Dew Point and VPD are calculated based on the measured temperature and relative humidity. You can view their values and trend curves on the History page.
If the Dew Point and VPD curves are not displayed, tap the gear icon in the upper-right corner of the History page to open Settings. Then tap the “+/-” icon next to each data type to show or hide the corresponding curves, including Temperature, Humidity, Dew Point, and VPD.
2. What is the battery life of the SNZB-02B?
The SNZB-02B is powered by 2 AAA batteries. Battery life varies based on usage and environmental conditions but typically lasts 2 years. To maximize battery life, ensure the sensor is within range of your Zigbee hub to minimize communication retries.
3. Can it be used outdoors?
SNZB-02B is not waterproof, and we do not recommend using it outdoors in an environment where it is easily wetted by water.


















































