Description Specs Features 4-Stage replacement filter for the of the PURINIZE PRO-5 10L Water Filter. This filter has four stages of filtration that trap harmful contaminants and help reduce bad odors, tastes, and other compounds. Stage 1: Activated Carbon Carbon has been used since ancient times (1200 BC) to purify water. Activated carbon is “activated” by heat and oxygen to create a high surface area that absorbs a broad range of contaminants frequently found in water. Stage 2: Zeolites Zeolites are microporous, aluminosilicate minerals with a unique cage-like structure that makes them useful in many ways, especially in water filters. Their ion-exchange and absorption properties are used to reduce odor and clean heavy metals and other natural compounds, like debris and sediment from water. Stage 3: Silica Sand Silica sand is commonly used in water filters because of its highly absorbent qualities to remove granular contaminants, suspended solids and colloids. Stage 4: Ion Exchange Resin In water purification, ion exchange resin is used to remove poisonous and heavy metal ions, replacing them with more harmless ions, such as sodium or potassium. Long-lasting Replace once every 6 months (or 500 gallons). Convenient Easy to insert & replace. No Maintenance Required.