Quality Dust-Free ReplacementTo Prevent Dust From Getting Outside, 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. Perfect Dust Pick-UpThanks To The Perfect Key-Lock Principle, No Dust Can Get Past The Miele Filterbag.