10 pack 16x25 MicroPower Guard Air Replacement Polarized Filters ( Actual Filter Size 14.5x22.5 ) Fast-Shipped-Filters. The original MicroPower Guard filter pad may have a target painted on it.  Since the manufacturer chose to use a cheaper Carbonized mesh rather than a full sheet of carbon, like the Dynamic Sales HVAC, they had to add a piece of foil as a target so the electrode would touch the foil and electrify the pad.  No worry with the Dynamic Sales HVAC brand replacement pads, you can load them any which way they fit and you will be sure to have a secure contact with the carbon sheet for optimal distribution of the electrical current.