Nut, Used for Switch, Relay, or Thermostat and so on, RoHS ... B18.2.2Grades: 2, 5, 6, 8, A194 2H, A194 4, and A563 DHSurface: plain, black, phosphate, zinc, hot dip galvanizing ... according to standard as well as non-standard ones Hex Nut with Phosphate, Hot Dip Galvanizing, and Teflon Surface