Profile: Ham-Let USA, Inc. specializes in instrumentation valves, fittings and other components. Our product line includes fittings, hightech components, process valves, check relies valves and quick connectors. Our LET-LOK™ range of connectors has been developed to fill the rapidly increasing demand for tube fittings suitable for high pressure use in environments such as petrochemical, fluid, power, nuclear, electronic, as well as other major industries. Our H-400 Series is a compact design for instrumentation panels and systems, which provides an accurate operating point. Our H-400 valves are normally closed. When differential pressure between inlet and outlet is higher than the set pressure of the spring the loaded poppet will move backwards and will enable a free passage of flow through the valve. It is equipped with brass construction with moderate pressure characteristic and compact design.