Neo-Pure SFR Series Single Filter Ring Nut stainless steel housings offer high quality, American-made 304L or 316L stainless steel construction for sturdy, long-lasting commercial and industrial applications. Ring nut closures offer easy and quick double open ended cartridge change-outs. Standard options feature FDA grade Buna N gaskets. Fresh Water Systems carries all sizes of Neo-Pure replacement filter cartridges needed to keep the SFR filled and in operation. Standard feature SFR series housings are in-stock and ready to ship.