Check Valve The design and production of the check valve fully complies with the requirements of API6A "Wellhead and Christmas Tree Equipment Specifications" and can be used with domestic and foreign equipment that complies with API6A specifications. The valve core is made of anti-sulfur steel material, so it can be used in an environment containing H2S. The valve body is made of alloy steel forgings with good performance. Jielin can provide two types of check valves: swing type and lift type.