I had to return this because the spirit level was inaccurate. Neither the horizontal nor the vertical plane was accurate. Here is Stabila's statement on accuracy.
Portable Handheld Manometer π for Accurate Pressure Differential Measurement
5 Review
π Dioxide Controller for Digital Gas Monitoring
5 Review
π‘οΈ Continuous Temperature Monitoring with Relative Humidity Integration
4 Review
π Enhanced Precision with Backlit Professional Manometer for Differential Ventilation
6 Review