Waterdrop Refrigerator Water Filter, Compatible with 3M Cuno CS-52, CS-51, CS-452, CS-522, CS-532, CS-562, CS450, CS-512, W1085590, 56932, 2168701, 51000, 52000, Pack of 2 NSF CERTIFIED: Tested and certified by NSF International against NSF Standard 42 for chlorine, bad taste and odor reduction. QUALITY PERFORMANCE: Premium coconut carbon block filter is certified to improve taste and quality of water. Delicate design ensures it perfectly fits the original without water leakage. FILTER LIFE: Our high-quality refrigerator water filter provides up to 6 months or 1500 gallons of clean and fresh water. REPLACEMENT MODEL: CS-52, CS-51& more. Waterdrop is an independent brand. This filter is not an original product. INTELLIGENT REMINDER: A professional fridge filter indicator is included in our new package, which makes remembering to change your filter effortless.