Easy installation: This pleated filter is easy to install right out of the box. Simply remove the old filter and replace it with this new MERV 16 Carbon filter Pleated filter design provides increased surface area for better filtration and longer life MERV 16 -rated filter fit Lennox PCO3-14-16 20x21x5 Actual Size: 20 x 20 5/8 x 4-3/8 Atomic is an independent brand and any reference to Healthy Climate or Lennox is used solely for demonstrating compatibility. Atomic Atomic 20x21x5 MERV 16 Carbon Filter Compatible Replacement air filters for your Lennox Healthy Climate PCO3-14. This Atomic 20x21x5 MERV 16 pleated air filter is comparable to the Lennox part Y6606 and 100908-12. The Atomic MERV 16 pleated filter is designed to perform as the OEM. Atomic filters are tested and certified by independent, third-party laboratories to meet or exceed the performance standards of OEM (Original Equipment Manufacturer) filters. Atomic is an independent brand and any reference to Healthy Climate or Lennox is used solely for demonstrating compatibility. Compatible with the following models: Lennox Part Y6606, 100908-12 Healthy Climate PCO3-14