20 Gallon Capacity, Vertical, Pressure Pump Tank, 38 PSI Precharged Well System, Lightweight Drawn Steel 2 Piece Shell With Ultra UV High Gloss Exterior Powder Coat, Bacteria Resistant Parabolic Diaphragm Eliminates Rubbing On The Diaphragm Or The Tank Wall, Attached Directly To An Interior Powder Coated Wall, Galvanized Acceptance Fitting Provides A 100% Corrosion Resistant Water Reservoir & A Reliable Water Tight Seal, Meets FDA & NSF 61-372 Requirements For Potable Water Supply, Durable Composite Base Eliminates Corrosion & Rotates For Easy Plumbing Alignment, Usable Water, Drawdown @ 30-50 PSI 6.2 US Gallons, 1" Female Pipe Thread Connection.