The Mitsubishi OEM replacement filter model MAC-1415FT-E is a two pack of replacement air filters for Mitsubishi Mr. Slim heat pump and air conditioning split systems that use a 13″ x 2″ x 1/4″ air filter. The actual size of the MAC-1415FT-E air filter is approximately 13-1/8″ x 2-7/8″ x 1/4″. This Mitsubishi OEM or Original Equipment Manufacturer air filter is a blue anti-allergy enzyme filter that attaches to the unit’s plastic framed pre-filter. The filter captures airborne bacteria, viruses, germs and traps fine dust, and pollen that the larger post-filter may not catch. This filter is made with a special enzyme to break down the bonds in allergen proteins, giving your home or office fresh air while reducing the presence of allergens in the environment. The MAC-1415FT-E pre-filter is used with the following Mitsubishi Mr. Slim split systems: MSZ/MSY-D30/36 The model number of your heat pump or series number of your indoor unit should be on the label on the bottom of your indoor unit. The Mitsubishi MAC-1415FT-E air filter media should be changed once every four months or as needed if sooner. Instructions on how to change your pre-filter come included with the filter packaging, or please refer to your unit’s Owner’s Manual. This package ships with 2 filters.