DIN Round Nuts -Metric , there are also other type of DIN standard, named Imperial etc, includling the male, liner and gasket.
DIN unions (Deutsche Industrial Norm) German standard fittings are used in conjunction with German and other european equipment.
DIN series Round Nut sanitary fittings, body material sanitary stainless steel 316L/304, Surface finishing 180 Grit ID/ 150 Grit OD. Fits to Sanitary Stainless Steel Tubing, seals a tube or hose fitting by welding. This ferrule welds to a fitting to help provide a leak-resistant seal on a tube or hose and then thread to a male fitting. Maximum operating pressure rating of 140 pounds per square inch (psi) @ 70 degrees Fahrenheit. Suitable for hygienic applications as food & beverage. When you design sanitary piping, consider the application, verifying material compatibility, shape, size, and duty. Tube fittings are used for connecting, shut off, controlling flow, and changing the direction of piping in the food, beverage, biotech, pharmaceutical, and other sanitary process industries to transport fluids through pipe lines and are available in a wide range of materials, finishes, and shapes.
Sanitary DIN Round Nut