CALL FOR QUOTES 1-800-504-6537 OR E-MAIL US AT: URBAN HART SALES DEPT ** ** ** ** ** ** ** ** Principles of Operation The PremAire Cadet Respirator is a pressure-demand device, meaning it delivers respirable air to the user "on demand." As such, it maintains a slight positive pressure of air inside the facepiece -- whether the wearer is inhaling or exhaling -- to prevent contaminants from entering the facepiece, should any slight face-to-facepiece seal leakage occur. Because the unit is a pressure-demand device, it can be used with a large, compressed air cylinder or a bank of cylinders set up in cascade fashion. For longer-duration air supplies, the respirator also can be used with a compressor that delivers respirable air to the user within the NIOSH-approved pressure range.