Electrolux Brisa Air Cleaner 510A / Z 7040Features : A very low noise level allows for bedroom use while sleeping. A low energy consumption means that you can leave this unit on 24h/7 days a week. The best combination of clean air production and lo noise keeps your home or office Allergen & Dust free without disturbing you day or night. Since this unit uses a carbon activated filter, it reduces tobacco smoke, kitchen smells and other harmful or bad smelling odors. With the noise audible indicator, you can set the unit to it's lowest noise setting when you are asleep and to work hardest in loud environments when the noise level is not noticed as much. This unit combines two technologies to accomplish it's great air cleaning. Using both an ionizer and electrostatic filter, this unit excels where other similar units fail. Some other models on the market use an ionizer or an electrostatic filter; this uses both.