The M-VF Series Safety Excess Flow Valve is engineered for fast, automatic shut-off in case of line, hose or fitting failures, protecting employees, plant, and valuable instruments. The M-VF Excess Flow Valve comes in five port sizes – 1/8", 1/4", 3/8”, 1/2” and 3/4” sizes, and the option to choose a FKM or FFKM o-ring for optimal chemical compatibility.Designed for protection of systems handling corrosive, toxic, radioactive and flammable materials, the excess flow valve will instantly detect surge in the system and stop fluid flow. When the line break is repaired and pressure is equalized in the system, the excess flow valve will open to allow the fluid to flow through the system. The M-VF Series Excess Flow Valve operates effectively with all fluids, liquids or gasses.