Industry Certified. The SGF-DSA21 filter is industry certified to NSF ANSI Standard 42. Environment in Mind. Swift Green is a brand committed to providing the most eco-friendly water filtration that also brings you the purest and healthiest water. All components of this filter are 100% recyclable! Most carbon filters are manufactured in a process called open pit charring, which releases pollution and greenhouse emissions into the air. Swift Green filters are produced with a new technology that carbonizes dried coconut shells in an enclosed, self-sustaining system while capturing and converting the emissions into useful thermal energy!