This pack includes a exhaust filter and one small round yellow motor filter for your ELECTROLUX upright vacuum cleaner @ease Z4236...Z4239 / AZ. The cassette filter captures even the very finest particles from entering the air while you clean, purifying the air leaving the vacuum cleaner reducing the risk of allergic reactions. The washable motor filter removes contaminates from the air before it cycles through the motor. For optimum performance of your vacuum cleaner, we recommend you replace all filters at least twice a year, or when they become visibly soiled.