This is a replacement filter for the Austin Air HealthMate Plus Junior . All junior size units are interchangeable with all junior size filters. So, if you purchased a junior size HealthMate® and would like to upgrade to a junior size HealthMate Plus, simply purchase a replacement HealthMate Plus Junior® filter. Filter Specifications STAGE 1 in Large Particle Pre-filter. Removes particles easily seen by the naked eye (e.g. dust, hair and pet dander). STAGE 2 in Medium Particle Pre-filter. Removes small to medium size particles (e.g. molds, spores and pollen) STAGE 3 in Over 270 cubic inches of Activated Carbon, Potassium Iodide Impregnated Carbon and Zeolite. Removes Volatile Organic Compounds (VOCs), formaldehyde, benzenes, chemicals, gases and odors. STAGE 4 in 30 sq. ft. of True Medical Grade HEPA. Removes 99.97% of all particles larger than 0.3 microns and 95% of all particles larger than 0.1 microns. You can check the size of your existing filter by looking for a label on the underside. Model HM200 indicates junior size filter.