Safeguard the air you breathe. IBR tests have proven Miele to be 99.99+% effective in both capturing and retaining particles 0.3 micron in size (that is 1/200th the width of a human hair) and larger. Original Sealed SystemTM Miele vacuum cleaners offer a true Sealed SystemTM, each individual compartment and the system as a whole are sealed with one continuous, durable rubber gasket. Miele's exclusive Sealed SystemTM design combines with the following three elements to ensure your indoor air quality: use of the very best raw materials available; unique, electrostatically charged filtering dustbag with an innovative spring-loaded collar that traps debris; a selection of high-quality filter cartridges, including a certified HEPA filter.