Ideal for allergy sufferers. Retains dust, pollen, bacteria, and other contaminants while you vacuum. This system combines a high-filtration paper bag lined with electrostatically charged fibers, and a Micro-Fresh filter pad to retain fine dust and pollen particles down to 0.1 micron in size. The air returning to the room is 99.9% fresh, based on laboratory tests. Type U , fits model No. 086335, M085570, Swivel Glide , and ultra.