Like Mother Nature, Sirena uses water as its filter. Separator technology forces air into the water, keeping dirt from being exhausted into your air. Dirt is trapped within the water. The air in your home is water-washed, and returned fresh and clean.Vacuuming with Sirena is a breeze. Begin by filling the basin with regular tap water. Make sure the water level is above the "MIN" line and below the "MAX" line. You can also add optional fragrances (from our Fragrance Pack) or a cap of our Ocean Breeze Deodorizer directly into the water before cleaning. Adding fragrances or deodorizer doesn't affect the cleaning efficiency. You can also switch the scents half-way through. Simply inject a few drops directly into the intake, there is no need to turn the machine off or to open the basin! Our Fragrance Pack includes four natural fragrances: Pine/Tropical/Apple/Eucalyptus.