Dürr Universal‘s ILF and ILFS Series Of In-Line Air Filters Are Designed To Withstand The Demanding Requirements Of Pressure And Vacuum Applications. The ILF and ILFS Filters Come In Standard Sizes Ranging From 3″ to 18″, With Flow Capacities From 275 to 9,700 CFM. Three Types Of Filter Elements Are Offered: Pleated Cellulose, Pleated Felt, Or Wire Mesh Media.