Carbon
 Pleated Air Filter for AC HVAC or Furnace. AF carbon filter, comparable
 with MPR 300 / 600 (clean living and dust & pollen). Two-piece 
frames are made of beverage board, which stays strong through humidity 
and temperatures with wire backed synthetic filtering media for optimal 
equipment protection and energy efficiency, these filters should be 
changed 60-90 days in periods of high use. These filters have a MERV 8 
rating: Removes dust, pollen, mold, dust mites and lint. Made in the 
USA.