Dayton Dome Filter, Cloth, Standard Filtration Type, For Vacuum Type Backpack Vacuum 4TR18 Capacity 600 C fold or 800 multi fold towels The door of the Bobrick The door of the Bobrick ConturaSeries Model B 4288 surface mounted multi roll toilet tissue dispenser was designed with the same arc and look as the rest of the Bobrick ConturaSeries lineup of commercial bathroom accessories The opening on the unit is hemmed for user safety They're usually found near the vacuum's exhaust port to catch fine particles that haven't been collected in the vacuum bag or dirt cup They filter fine particles from the vacuumed air as it exits the vacuum's exhaust port