GE’s NSF-certified Namtso replacement refrigerator water filter is the improved version of the GWF model, providing you and your loved ones cleaner, healthier, and better-tasting drinking water at home. By reducing contaminants like mercury, toxaphene, p-dichlorobenzene, carbofuran, alachlor, benzene, lead, cryptosporidium, and giardia, the Namtso is a safe and affordable way to contribute to a healthy lifestyle.