Water Source CV-150NL Spring Loaded Check Valve, No Lead, Brass, 1-1/2"The 1 1 2 inch brass check valve keeps prime in jet, submersible, and centrifugal pumps. When a pump shuts off, the check valve closes preventing the water from traveling back to the source. This check valve is constructed of heavy brass material. 1 1 2" Solid brass Keeps prime in jet, submersible, and centrifugal pumps Spring loaded Solid brass design meets federal low lead regulation Vertical or horizontal application prevents back flow to the pump.