The MicroPower Guard® uses an active electromagnetic field to magnetize both airborne particles and the fibers of the disposable filter pad. This creates a virtual “force field” within the ductwork, capturing many of the smallest, most dangerous to breathe submicron airborne particles. When the air is recycled through the MicroPower Guard in your ductwork, this air cleaner will remove 97% of particles at .3 microns. This 1″ filter is the most cost effective and easiest to maintain electronic air cleaner available for the Nature’s Home® and is an essential component of any Premier air purification system. Each disposable filter pad remains at peak operating efficiency for about four months before needing to be replaced.