These vacuum bags have ultra-micro filtration for health and cleanliness.  Comes in a 5 pack of open-top elastic rimmed bags.  They are a paper cotton blend that are great for people with allergies.  One size fits all, including Silent Master, Modern Day, Flo Master, Air Force and Air-Flo brands.  Replaces the following bags: 721H-5, 720-5, 720H-5, 720HF-3.