Xiamen Dervos Valves Co., Ltd Main Products:. Ball Valves, Butterfly Valves, Check Valves, Gate Valves, Globe Valves, Plug Valves, Angle Valves, Knife Valves, Marine Valves, Needle Valves, Steel Pipe, Flange which was built up in 2007. The professional sales and service team started the business in valves from then on and has expanded the markets to Europe, South America, and Asia.