The Diamond Spot Anvil is recommended for supporting thin, soft sheet metal. The center of the anvil has a flat polished diamond surface (3/8in [9.5mm]). As the sample deforms under test the load, this surface standardizes the frictional effect between the anvil and sheet metal. The diamond Spot anvil should only be used with a ball indenter on the Superficial rockwell scale. The Diamond Spot anvil must NOT be used with diamond indenters.