Waterway 3 1 2" Hi Flow Suction Assembly [w Hex Nut] [w O Vacuum Brk] [2 3 8" HS, 1 1 2" Slip] [Gray] (640 3257V) americanpool A pressure switch tube is A pressure switch tube is useful because it helps transmit the pressure condition to the switch this impeller helps restore dependable water movement and contributes to a stronger pump repair overall This Waterway assembly is a practical replacement when the original 3 1 2 inch Hi Flow suction fitting needs a direct gray renewal with the same no vacuum break and hex nut configuration The Waterway 640 3257V Hi Flow suction assembly is designed for compatible 3 1 2 inch applications and features a hex nut