The Frigidaire Pure Source Ultra water filter reduces up to 99% of impurities from your drinking water! For up to six months after a trouble-free installation, the Frigidaire ULTRAWF refrigerator water filter will reduce chlorine, mercury, lead and more potentially harmful contaminants that can impact the quality of drinking water served by your fridge. the Frigidaire ULTRAWF also serves as an exceptional upgrade for refrigerators requiring the Pure Source 3 WF3CB filter.