20 Gallon Capacity, Vertical Pressure Tank, Precharged Well System, Heavy Duty Steel Shell With High Gloss Enamel Finish, Bacteria Resistant Butyl Rubber Diaphragm With Seamless Construction For Uniform Strength, Polypropylene Liner & Copper Lined Acceptance Fitting Provide A Corrosion Resistant Water Reservoir & A Reliable Water Tight Seal, Meets FDA Requirements For Potable Water Supply.