This method involves two molds, one male, and one female. A heated sheet of plastic is held between the two molds and the molds are brought together. No vacuum or air pressure is used because the molds themselves do all of the forming. The space between the two molds determines the parts thickness and produces excellent detail on both sides of the part. The molds are usually then cooled, preferraby internally, before they are separated and the part is ejected.