2-ply electrostatically charged filter media captures particles down to .10 micron at 85% efficiency, ensuring a clean and healthy environment for your family. Fits Models: all Nutone models including CV350, CV353, CV450, CV750, PP500, PP600, PP650. Does not fit model CV850, NuTone CV350, NuTone CV352, NuTone CV353, NuTone CV450, NuTone CV653, NuTone CV750, NuTone PP500, NuTone PP600, NuTone PP650, NuTone PurePower, Eureka CV1004B, Eureka CV1804B, Eureka CV1601M, Rittenhouse CV130. Quantity Per Package: 3. Replaces part no : CF3918, 110025 and 110056, Nutone-391 and 44186 bags.