https://www.wsv-valve.com/products/check-valves/
Check valve is a valve referred to the opening and closing parts for the circular disc and by its own weight and medium pressure to block the media flow back.
Elliot Jensen and Elliot Fintry have a lot in common. They share the same name, the same house, the same school, oh and they hate each other but, as they will quickly learn, there is a fine line between love and hate.