Lifegard Replacement filter pad material is bonded to keep its original shape, It has superior filtration with uniform and consistent material and filters all size of particulate matter, Instructions: Make a pattern out of cardboard or paper to match the size of your filter box opening, Place a pattern on the filter pad material and cut 1/4"" larger on all sides for a snug fit, Insert pad into filter Blue side up, for even better filtration, cut 2 pads and sandwich a bed of Lifegard Activated Carbon between the 2 pads, Size: 24"" x 15"" (360 sq, in, ) SKU: RPS21099