Review on Quality Particle Sensitivity Detector Analyzer by Roberto Manzer

My device is defective. It worked the first day, and then it didn't work except a couple of times. The possibilities to communicate with this seller are very limited. I could only post one question. They answered my question very slowly. The seller's response indicated that I couldn't figure out how to press the start button and that I didn't understand that each read takes 120 seconds. It should be obvious that if it worked for me on day one, I knew how to handle it. Too bad. It matched my hygrometer pretty well, but particles are my biggest concern.