BOSCH VB090 Paper Dust Nag for 9 Gallon Dust Extractors (5 Pack). Filter bags act as a primary filter, capturing large pieces of debris and increasing the life of the main filter. Using a filter bag is the most efficient way to dispose of the captured dust and debris. Each VB090 Bosch Paper Filter Bag comes with a port cover which securely closes opening of the filter bag and keeps the dust and debris inside during the disposal process.