Replacement compatible Professional Air Filter for Projectors/Car Cabin Air Filter/Air-condition DIY Size Replacement compatible Professional Air Filter for Projectors/Car Cabin Air Filter/Air-condition DIY Size Comparing with sponge material air filter, this listing have the following advantages: Remove (from the air that passes through) 98% of particles that have a size of 0.3 m Cut the filter to fit the frame, it can be used for at least three times, much cost effective. When you paste the air filter, be minded the rougher surface faces outward, the smoother surface faces inward