The Neeco NMS Check Valve is a reduced opening lift type valve, top-entry only, which permits fluid flow in only one direction. It is designed to have an extended life due to its streamlined seat which causes the fluid impact to be reduced. The NMS valve contains a metal-to-metal sealing superior to the rubber sealing found in other check valves. Neeco designed the NMS in accordance with API- 6A and NACE MR-0175 for H2S Service.