BACOENG 4 Gallon Reverse Osmosis RO Water Storage Water Systems TANK 1.Pre-pressurized 4 Gallon Water Storage Tank (holds up to 3.2 gallon of water). 2.Discharge efficiently in a vertical or horizontal position with tank stand. 3.FDA approved food grade bladder and NSF Certified to ensure quality, safety and durability. 4.Inlet/Outlet Connection: 1/4" Male Pipe Thread. Special designed for RO application.