the minusa2 with biogs hepa technology was built with versatility in mind. at a mere 7 inches in depth, it does not interfere with your personal style and is virtually silent in sleep mode to ensure a peaceful night’s sleep and maximum efficiency. with a six-stage air filtration system and a selection of four customized filters, (pet allergy, germ defense, toxin absorber, and odor remover) the minusa2 is designed to accommodate a wide range of allergies and sensitivities. a long-lasting filter system and energy efficient design make the minusa2 incredibly affordable to maintain. just vacuum the surface of the pre-filter once a month and change the filters every one to two years.