Penn Plax Polyfiber Filter Media Pad, 30 by 18-Inch FOR CRYSTAL CLEAR WATER: the thick and dense material of this Polyfiber filter media pad allows it to trap coarse and fine debris from your tank. MEASUREMENTS: made to be trimmed to fit your needs, the product is 30 x 18. MADE FOR ALL YOUR FILTRATION NEEDS: the filter media pad is made for freshwater and marine aquariums as well as ponds. FULL LINE OF MEDIA PADS AVAILABLE: sold on Amazon, there are carbon, ammonia remover, nitrate remover, phosphate remover, and polyfiber plus pads, by Penn Plax. Each sold separately. SHOP PENN PLAX FOR ALL YOUR PETS NEEDS: Penn Plax is a manufacturer and distributer of top pet supplies, who specialize in creating excellent pet products for animals both great and small.