Ionic Breeze Quadra Silent Air Purifier, Original Silent Air Cleaner, Now with OzoneGuard - Gray (SI837GRY) Silent operation. Circulates air electronically, no motor, no fan, no noise. Very low cost to operate - uses 10 watts. About $10 per year with 24/7 operation. No filters to replace. Unit traps particles on a stainless steel collection blades which easily wipe clean with a cloth. OzoneGuard with PermAir catalyst converts by product ozone to oxygen. UL Listed (46AT) and Intertek Listed (980143).