The Lennox OEM Y6607 PCO3-20-16 Healthy Climate PureAir Air Purification System Metal Mesh Insert Cartridge features a Precision Pleat MERV 16 cartridge that traps particles down to an amazing 0.01 micron. This hardworking furnace cartridge eliminates 95% of troublesome particles possibly contaminating the inside air of your home. Harmful particles such as pet dander, dust, pollen are a thing of the past with this workhorse of a cartridge. The Y6607 also does a number on microorganisms such as viruses, mold spores, dust mites, and bacteria. Lennox recommends this cartridge be replaced every 12 months for optimal performance throughout your home.