Filter-Monster branded replacement compatible with Austin Air Allergy Machine Junior FR205 Air Purifier filter. Fits Austin Air models HM205, HM200, HM250. Package contains (1) filter, two (2) pre-filters. Approximate Dimensions - Diameter: 9.8", Inner Diameter: 5.5", Height: 11.50". Filter-Monster branded replacement filter compatible with Austin Air Allergy Machine Junior FR205 Air Purifier filter. Recommended to change filter once every five (5) years for maximum efficiency, or more often in harsh environments. Package contains one (1) filter and two (2) carbon pre-filters. Engineered to fit Austin Air Allergy Machine Junior (HM205) Air Purifier. Also fits Austin Air models HM200, HM250.