Filter-Monster branded replacement compatible with Austin Air Pet Machine (FR410) filter. Fits Austin Air models HM410, HM402, HM405, HM400, HM450. Filtration removes up to 99.97% of airborne particles as small as 0.3 microns in size including dust, smoke, pollen, pet hair and dander, mold spores and dust mites. Recommended to change filter once every five (5) years under normal conditions, and more often under harsh air conditions. Package contains (1) filter, two (2) pre-filters. Approximate Dimensions - Diameter: 13.5", Inner Diamter: 7.25", Height: 14.5". Filter-Monster branded replacement filter compatible with Austin Air Pet Machine FR410 Air Purifier filter. Package contains one (1) filter and two (2) carbon pre-filters. Engineered to fit Austin Air Pet Machine (HM410) Air Purifier. Also fits Austin Air models HM402, HM405, HM400, HM450.