is the measure of the hardness of a petroleum wax, utilizing a penetrometer. Penetration is reported as the depth, in tenths of millimeter, to which a standard needle penetrates the wax under conditions described in test method ASTM-D-1321. Prior to penetration, the wax sample is heated to 17°C (30°F) above its congealing point, air cooled, then conditioned at test temperature in a water bath, where the sample remains during the penetration test. The test temperature may range from 25°C to 75°C (77°F to 130°F).