You might have better luck. I suggest ordering three gauges and three calibrators. If they all match, you're good. So far I have two defective sound pressure level meters. It was one of them. I also bought a calibrator which is equally inaccurate at all three meters. Let's see if the following two calibrators agree.
Portable Pressure Measurement Measuring Momenturn
10 Review
π Cadrim Digital Sound Level Meter: Accurate Measurement and Noise Control Solution
6 Review
π Digital Sound Level by Parts Express
6 Review
π Enhancing Accuracy on the Go: Introducing Protmex Portable Measurement Accuracy Selection
7 Review
Airthings 2960 View Plus Humidity Sensor
3 Review
π BIAOLING Accurate Formaldehyde Multifunctional Test: Record, Measure, and Inspect with Confidence
3 Review
Airthings Wave Indoor Quality Monitor
3 Review
π¬οΈ BIAOLING Accurate Formaldehyde Multifunctional Recording: Say Goodbye to Indoor Air Pollutants!
3 Review