Poly-Bio-Marine Poly Filter Pad, 4" X 8", Five PackBrand: Poly Bio Marine Details: This is a Five Pack Bundle. The Poly Bio Marine Poly Filters are a formulation of a special patented material bonded to a synthetic matrix. By means of a unique proprietary process, the Poly Filter is made impervious to salt and is also organic loving to certain materials. The Poly Filter pads absorb and adsorb contaminants and other toxic materials found in nature or added to fresh and salt water with or without fish