SF Filter (Shuangfa) is one of the earliest filter manufacturer in China, established in 1991, product certified by NSF since 2015, WQA membership since 2016, focused on filter cartridges for water/liquid filtration and purification. We believe in data, at SF, research and quality control protocols are developed based on performance. Our product includes String wound filters, PP melt blown filters, activated carbon filters, membrane pleated filters and water filter system.