When I got back into turning in 2007, I was a registered respiratory therapist, and I wanted the best protection that I could find and afford. I bought the Trend Airshield Pro based on my research of what was available at the time. I still use it everytime I create dust. The earmuffs don't fit well, and after many uses and recharges, the battery pack needs replacement...and not a cheap pack either. Of course, it's proprietory, so no substitutes available. I now also have a hanging air filtration system, and also a point source dust collector. You only get one pair of lungs as original equipment.