The Black & Decker BXAP62002GB Air Purifier with Air Quality Sensor has 3 built-in air purification filters which capture particles remove allergens and kill bacteria to improve air quality. The carbon filter helps cleanse unpleasant odours to refresh your room’s scent. Select from sleep high or automatic air purification modes for effective cleansing indicated by 3 LED lights which displays the amount of air pollution in the room. An 8-hour timer can be set to automatically shut down the device to save energy. Designed to operate quietly the air purifier produces only 25 decibels on the lowest setting while the filter change reminder indicates when a replacement is required.