This Omnipure Q-Series Water Filter is a replacement water filter and must be used with an existing Q-Series Water Filter head. The Q-Series heads areavailable in Valved OR Non-Valved, 1/4" Quick-Connect Fittings, 1/4" FPT or 3/8" FPT female pipe threads. Q5733, 2.5"x14", 12x40 Mesh, T33 Acid Washed GAC, 3000 gal/1 year, . 5 gpm, Omnipure Q-Series Water Filter, Post RO