Poly sheet is highly adsorbent chemical filter media pads quickly and efficiently remove impurities, medications and phosphate from aquarium water;Use in conventional power filters, under gravel filters, the chemical filtration compartment of canister filters and wet/dry filters;Simply cut to any size or shape to custom fit any aquarium filter;Rapidly improves water clarity and actively removes harmful organic and various inorganic waste buildup for several months;Measures 4-inch length by 8-inch width. 3 individual packages