Micrometer anvils today are covered in a layer of carbide material. For a long time, micrometer anvils were made out of steel and you can still find a number of steel micrometer anvils today. However, steel is not as durable a material as carbide and so many of the anvils made today are covered in a layer of this more enduring substance. Carbide material consists of carbide mixed with another material with a lower electronegative property. As compared to steel, carbide material comes with important advantages for lasting accuracy when using your micrometer anvil. First, the melting point of carbide is more than 1000°, second, carbide has a significantly lower thermal expansion point than steel, and third, carbide has a density and a hardness level twice that of steel. These qualities increase the durability and reliability of the micrometer anvil, making it the most commonly used material today.