Filter-Monster branded replacement compatible withAustin Air Bedroom Machine FR402 Air Purifier filter. Fits Austin Air models HM402, HM410, HM405, HM400, HM450. Package contains (1) filter, two (2) pre-filters. Approximate Dimensions - Diameter: 13.5", Inner Diameter: 7.25", Height: 14.5". Filter-Monster branded replacement filter compatible with Austin Air Bedroom Machin FR402 Air Purifier filter. Package contains one (1) filter and two (2) carbon pre-filters. Engineered to fit Austin Air Healthmate (HM402) Air Purifier. Also fits Austin Air models HM410, HM405, HM400, HM450.