Non-returning valves are allowing the liquids to flow in one direction. But when the flow cease, block it’s way to flow back. A spring inside will open by the kinetic energy of the flowing liquid, allowing it to flow through. The profiles are made of brass copper.

You can select from the listed products here

1/2″ non-returning valve

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3/4″ non-returning valve

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1″ non-returning valve

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5/4″ non-returning valve

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6/4″ non-returning valve