Distillates (petroleum), acid-treated heavy naphthenic; Unrefined or mildly refined baseoil; [A complex combination of hydrocarbons obtained as a raffinate from a sulfuric acid treating process. It consists of hydrocarbons having carbon numbers predominantly in the range of C20 through C50 and produces a finished oil with a viscosity of at least 100 SUS at 100 °F (19cSt at 40 °C). It contains relatively few normal paraffins.]