gaskets Surface Treatment:Galvanized,Bright,Black-coated. Standard:Chinese,America,Germanic ... from scratches nuts, spread nuts on the connector pressure.Standard Gaskets:Surface Treatment :Galvanized ,Black-coated,Bright.Standard:Chinese,America,Germanic ... 0.3mm and 22mm of thickness.We also can produce flexible gaskets,of which surface treatment the same with standard gasket. Flat ...