This device is very different from other air purifiers on the market. This is focused on keeping the air clean that you breathe at night while sleeping as opposed to trying to clean the air in the whole room. Think of it as a personal space air cleaner.
The PureNight Pure Air System uses “laminar flow” technology to bathe you in an envelope of 99% pure allergen-free air. The system consists of a 6½ inch tall HEPA filtration unit that slides underneath your bed and is connected to a vertical column to a horizontal laminar arm that extends over the head of the sleeper. The filter does need to be changed every three months.