MMC is the world’s leading manufacturer of portable instruments for measuring ullage, oil-water interface, temperature, and bottom dryness in shipboard and land-based petroleum and chemical tank systems. All MMC systems are manufactured in the United States and are certified as intrinsically safe by BASEEFA and CSA. The Portable Closed Flexi-Dip measuring tape is a battery-operated electronic unit that is completely gas-tight. When installed in a vapor control valve mounted on a storage (cargo) tank, it forms a tightly sealed system that prevents toxic vapors from escaping and creates a closed gauging system for that tank. The tape is marked in metric or imperial units and is anti-static coated, as is the sensor. Furthermore, the tape is color-marked to make tape direction and motion easily visible and to ensure full rewind position. A coiled grounding cable with a large alligator clip is standard. This closed system is recognized by many worldwide regulatory bodies as equivalent to a fixed gauging system, as long as the tape remains in the valve from the beginning until the end of loading or discharging of the tank.