RayAir Supply 20x25 Dynamic Air Cleaner Replacement Filter Pads 20x25 Refills (3 Pack) FREE Shipping Three (3 Changes) fiberglass media pads with activated carbon center per order. Dynamic Compatible Replacement Media for a 20x25 Filter ACTUAL REPLACEMENT PAD SIZE 18.5" x 22.5" Quality Materials Locate the<u>size label located inside the c-channel</u>at the top of your Dynamic Air Cleaner. If the Size Label indicates <span class="a-text-bold">20x25</span>or Media Pad Part Number<span class="a-text-bold">C3P2025</span>, these are the correct size replacement pads. If the Size Label is missing - Simply measure the frame Width x Length. <span class="a-text-bold">NOTE: The actual dimensions of a 20&#034; x 25&#034; filter frame are actually 19 5/8&#034; x 24 5/8&#034;.   </span> The replacement filter pads measure approximately 1  x 2  smaller than the filter frame size. Replacement filter pads are designed smaller in order to fit within your 20 x 25 air cleaner frame. <span class="a-text-bold">Product Description:</span>This high quality compatible replacement media is for use in a: Dynamic Air Cleaner* These air cleaners utilizepolarized media technology enabling it to capture submicron respirable particles that can trigger allergic reactions. This design provides for simpler filter media changes while still removing the smallest (submicron) particles. Based on average service conditions, approximately 3-4 months between filter cleaning has been shown to be effective in maintaining adequate ventilation flow. <span class="a-text-bold">Material:</span>The fiberglass media is manufactured from 100% recycled crushed glass known as cullet.&#034; The continuous glass fiber manufacturing process eliminates the potential hazards of respirable fiberglass particles within the media pad. The diameter of each fiber is greater than 18 microns which is well above the 3.5 micron size that has been attributed to health concerns. <span class="a-text-bold">How does it work?</span>When particles such as dust, pet dander and household chemicals pass through the filter, they become polarized. These polarized particles join together to form bigger clusters that are more easily captured and collect on the fiberglass pad with an activated carbon center screen. The full sheet activated carbon center media pad is a non-woven polyester base fabric. The fiberglass media becomes polarized by the charge from the power supply and acts like a powerful magnet to attract sub-micron particles.