Provides annual protection against costly water heater scaling and sediment build-up. Siliphos® Polyphosphate media prevents (sequesters) water hardness from scaling on flash heating surfaces. A dual-gradient 50 over 5 micron filter reduces sediment, which can cause additional scaling throughout the hot water line. The gradient density filter design provides up to three times the dirt-holding capacity of similar size sediment cartridges. The unique micro--fiber filter construction delivers higher filtration efficiency and flow rates. Ideal for indoor and outdoor installations. Features a 1-1/2” NPT inlet/outlet with a pressure-change gauge for peace-of-mind.