An API 598 Check Valve is a type of valve designed to meet the standards outlined in the API 598 specification, which covers inspection and testing requirements for resilient-seated, nonmetallic-seated, and metal-to-metal-seated valves. Check valves are integral components of fluid systems, allowing fluid flow in only one direction while preventing backflow. Typically featuring two openings—one for entry and one for exit—these valves play a critical role in ensuring the unidirectional flow of fluids.