Vacmaster HEPA Cartridge Filter Assembly, VKHF001 HEPA certified cartridge filter removes 99.97% of all particles greater than 0.3 micrometer from the air that passes through HEPA filters are beneficial for people with allergies and asthma since it traps the fine particles which trigger allergy and asthma symptoms Disposable pre-filter bag helps prolong the life of the HEPA cartridge filter Compatible with Vacmaster VK811PH and VK1011SIWTH Includes 1 pre filter and 1 HEPA filter