The IRIS WMF 617 washing machine filter is a multi layer filter that comes with best in class anti-scalants & dual sediment filter layers. It ensures that suspended impurities are filtered out and hardness salts are conditioned before they reach your washing machine. Instead of sticking to each other and forming crystals (what you see as white deposits on tiles and bath fittings) they are converted into less stubborn, fine particles that easily wash away.