Mine wasn't as accurate as other reviewers have said, plus one arrived with a cracked display. I used a jar with packets at 62% relative humidity. Leave them in a closed jar for 2 days. I also put a more expensive reader in a jar for them. My more expensive sensor showed 62%, as did one of them. 3 of them read 60. The rest were @59 with one at 58. Close enough I think.
Wintact Handheld Anemometer Small Digital Vane Wind Speed Meter Gauge, Pocket Air Flow Velocity Tester With Measuring Wind Temperature 14℉ To 113℉ For House HVAC Duct Outdoor Kite Boat Sailing Surfing
18 Review
Xiaomi Mijia Hygrometer Bluetooth Global Thermometer, white
32 Review
Room temperature and humidity sensor Aqara Temperature and Humidity Sensor
59 Review
Precise Humidity Control With Xikar PuroTemp Round Digital Hygrometer, 10-Second Refresh Rate
27 Review
Stay Cool With COMFYHOME 3-In-1 Portable Air Conditioner - Efficient Evaporative Air Cooler For Home And Office
11 Review
Senville AURA: Energy Star Mini Split Heat Pump W/ 9000 BTU & Alexa Compatibility
13 Review
Split system Roda RS-AL09F / RU-AL09F
37 Review
White Senville Dual Zone Mini Split Air Conditioner Heat Pump, 28000 BTU, Alexa Compatible - SENA-30HF/D
21 Review