This filter is the "inside” of the jet air purifier. The outer filter should be changed frequently (I use economy filters for large box ovens) and the inner filter can be washed from time to time. Over time, the internal filter becomes unusable and needs to be replaced. This replaced the original so I've racked up plenty of miles with it and I'm happy to say the replacement looks like it will stand the test of time. The fit was perfect as you would expect from an OEM product. Overall I'm very happy with the update.