Quality Perfect Dust Pick-UpThanks To The Perfect Key-Lock Principle, No Dust Can Get Past The Miele Filterbag. HycloseSo That You Avoid Contact With The Dust, The Filterbag Closes Automatically When The Appliance Is Opened. Dust Is Securely ContainedThanks To Several Filter Layers (Gentle) Dust That Has Been Vacuumed Up Cannot Escape Into The Room Air. Airclean Filter SystemThe Miele Airclean System Filters More Than 99.9% Of All Fine Dust Particles.