The Prince Wolverine check valve is designed to provide flow in one direction. The valve body is made of carbon steel for tensile strength and hardness. It has female NPT threads for connecting to male threaded pipes, creating a tighter seal than straight threads. The maximum pressure rating is 5000 pounds per square inch (psi), and the working temperature range is -20 to 210 degrees Fahrenheit. Check valves have two ports and restrict the flow of fluids and other loose materials through a pipe or passageway to one direction. Flow enters through one port and exits through the other, closing when flow reverses or stops. Two common types of check valves are ball cone valves and swing check valves. A ball cone valve utilizes a spring-loaded ball seated against a cone-shaped interior surface to stop the flow of fluid in a forward direction, and a swing check valve has a movable disc on a hinge to block reverse flow. Check valves are rated by their cracking pressure (the minimum upstream pressure required for the valve to operate), and they are used in various water, gas, air, and steam lines. Prince manufactures hydraulic cylinders, valves, pumps, and motors. The company, founded in 1950, and headquartered in North Sioux City, SD, meets International Organization for Standardization (ISO) 9001:2000 standards and is certified in engineering and manufacturing for the fluid- power industry.