Penn Plax Cut To Fit Poly Fiber Plus is an 18 in. x 10in pad that you can cut to fit in any filter. With its thick dense material, it helps strap coarse or fine debris particles. For Crystal clear water, while helping to improve water quality.From the manufacturer:Penn-Plax is a family-owned business that was established in 1956 in Brooklyn, New York. Over the years our goal remains the same: to enhance the pet ownership experience.We specialize in creating excellent pet supplies for animals, both great and small. We're best known for producing pet products at affordable prices. Our brand, Penn-Plax, is synonymous with innovation and quality, keeping your pet foremost in mind.