Click here for discount & review from Amazon buyer : www.amazon.com Replace filter every six months. Filter life may vary depending on use and local water conditions. Do not use with water that is microbiologically unsafe or of unknown quality without adequate disinfection before or after the system. Systems that are certified for cyst reduction may be used on disinfected water that may contain filterable cysts. Individuals requiring water of certain microbiological purity should consult their physician. I’m always a little afraid to order substitute brands, but the price and the picture of the Pur Filter product gave me a little more confidence to give it a try. But once here it fit my Kitchenaid Side-By-Side Refrigerator perfectly and was easy to install. Would recommend this replacement product to others. PUR QTSS Whirlpool Quarter Turn Refrigerator Ice and Water Filter Cartridge