
Installed three of these devices in my camper the day before the trip. I couldn't read them when I got to my camp. The bubble disappeared in all. Useless.

π Dioxide Controller for Digital Gas Monitoring
5 Review

π Enhanced Precision with Backlit Professional Manometer for Differential Ventilation
6 Review

Portable Handheld Manometer π for Accurate Pressure Differential Measurement
5 Review

π¬οΈ Advanced 3-in-1 Indoor Air Quality Monitor with CO2/RH/Temp Data Logging and Audible Alarm - NDIR Sensor Technology
8 Review