The Carrier FILXXCAR0024 compatible filter fits the Carrier FILCAB mechanical air cleaner, MPKA series and any other 24"L x 25"W x 5"T box filter. This media filter is a whole house filter which is attached to the HVAC system. It has a MERV 13 filter efficiency value, which indicates how minute the particles that can be trapped by it. The higher the rating, the finer the filtration and the fewer the particles that pass through it. To further increase filtration, it has a pleated rather than a flat surface, thereby increasing the filtering surface area. This efficiently traps airborne minuscule particles such as dust, pollen, dust mites, lead, animal dander, smog, insecticide dust, mold spores, smoke and even bacteria and microscopic allergen as small as 0.3 microns. An additional benefit is that an air filter will also extend the life of your heating and cooling system by making it work more efficiently by preventing the accumulation of particles that settle on the evaporator and condenser coils.