Six-pack of the PowerQUAD Standard Cartridge Filter is ideal for most industrial and commercial cleaning applications. Provides filtration of 10 microns @ minimum of 98% efficiency. Fits all Guardair PowerQUAD 55, 30 and 20 Gallon Drum Vacuums and Vacuum Generating Heads. For finer filtration, substitute HEPA Cartridge Filter or ULPA Cartridge Filter.