Pentair Autofill, Gray | T40BG Natural Chemistry The part number 400-4000 describes

The part number 400-4000 describes a Union Fitting that connects two 1-1/2 in socket ends

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Pentair Autofill, Gray | T40BG Natural Chemistry The part number 400-4000 describesWhat This Part Is Used For The Pentair T40BG Autofill Gray maintains proper pool water level automatically. It compensates for evaporation through a mechanical float system. Why This Part Matters Consistent water level prevents suction issues and equipment strain. An autofill reduces manual filling and stabilizes operation. It supports reliable skimmer and pump performance. Key Features and Specifications Pentair manufacturer part number: T40BG