Threaded swing check valves are main products made by Yongyuan in China. These valves are designed to prevent backflow of liquid or gas in pipeline. Materials of construction conform to NACE MR0175. Solid stainless steel clapper and hanger reduce the need for separate pins and rollers. They’re available in sizes 1” to 4”, pressure from 2000psi to 5000psi. NPT threaded ends are on both sides.