It's cheap in both price and quality BUT it works well as a spirit level. I use mine at work and if I lose one I don't lose a lot of money. Don't expect quality and sophistication for $20. It's only a few bucks, folks. Don't whine and don't whine. Now I have some good ones for home use.
Portable Handheld Manometer π for Accurate Pressure Differential Measurement
5 Review
Digital multimeter RGK DM-12
6 Review
π Enhanced Precision with Backlit Professional Manometer for Differential Ventilation
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π¬οΈ Advanced 3-in-1 Indoor Air Quality Monitor with CO2/RH/Temp Data Logging and Audible Alarm - NDIR Sensor Technology
8 Review