Circupool SJ-20 Salt Water Pool Chlorine Generator Made in USA, with industry-leading cell lifespan and unmatched 5-Year Limited Warranty. Reverse Polarity Self-Cleaning Cell, Maintains pool to up to 20,000 gallons max under ideal conditions Monitors performance & salinity level - works on the widest available salinity range. Easy DIY installation with no warranty penalty.Vector Jet maximizes effectiveness. No other salt system is as durable, user-friendly, and easy to operate.