Bests & Worsts Reviews from Amazon

I have now bought several of these and have provided to friends and family. I used one on my first post pandemic flight myself and felt more comfortable that I was protected. I believe that after making minor modifications, the unit provides better filtration than an N95 mask alone because the positive pressure reduces the amount of leakage around the mask when you inhale. It also just feels more comfortable with the provided airflow. Since I am an engineer who was recently designing similar larger devices, I tested this filter with a laser particle counter looking for 0.3 micron particle size. I found that some air could bypass the filter around various leak paths. Covering the usb charge port during use was an improvement but finally I found that I could solve the issue with silicone caulk applied around the pcb inside under the filter. I have modified several this way now and confirmed performance. Prior to that modification, the filter performance was worse at high speed than low speed and sometimes marginally N95 caliber. After the modification, I get very low particle concentration around 200 particles per cubic foot in a room with background count around 500,000 particles per cubic foot. Prior to the change I was counting around 6000 - 8000 particles per cubic foot. So the bottom line: It IS more protective than an N95 filter and more comfortable. Its true that the tubing can kink and I suppose it could tear. So far I have not had those issues. I used a 3/8" leather punch to make more masks for it and found a different style mask that worked a little better for me. I have also measured the airflow rate with a hot wire anemometer and though there is some measurement uncertainty, I can affirm that its in the range of 2.5 - 3.0 CFM on the high setting.