Activated carbon pad. Can be cut to fit air purifiers Help remove odors from pets, smoke, cooking, and more Dimensions of the filter: approx. 17.5"x 11.8" and 0.4" thick (inches) Package includes: 2 pcs of filter pad. activated carbon is extremely porous with a very expansive surface area. As air flows through it, impurities are adsorbed on the surface of the carbon by surface electrostatic attraction and capillary action.