Series PWRO440 uses advanced design with state-of-the art technologies and high-quality components to assure years of trouble-free performance. Includes many standard features that are only available as options on other reverse osmosis systems. Features include: powder coated steel frame; inlet solenoid valve; 20-in. prefilter; prefilter pressure gauge; multistage centrifugal pump; low-pressure protection with microprocessor auto reset; tank level input (dry contact); [retreatment interlock input (dry contact); 2 1/2 in. liquid filled pump pressure gauge; stainless steel pressure vessel(s); product flow and reject flow meters; concentrate needle valve; non-metallic recycle needle valve; and feed water and product water TDS monitor. Also includes input for auto shutoff when storage tank is full and input for auto shutoff when pre-treatment is in regeneration. Applications include whole house filtration, boiler feed water, humidifiers, greenhouses, process water, electronics, and spot-free car washes.Connection Size: 3/4 in. (20mm) Max. Productivity: 2,200, 4,400 and 6,600 gallons per day