For over 40 years, Hy-Lok USA has been supplying our partners with hard-working, adaptable, and robust instrumentation tube fittings and valves. We understand that you work in industries where there is little margin for error, so you need equipment that will consistently perform in a variety of challenging conditions. That is why we have scoured the globe for the best available alloys and materials, which are built to work as hard as you do.