Common Heidelberg machine models produced are MO series, S-Line, SM or SpeedMaster series and CD or Cardboard Diameter line of machines. The series or model of the machine is usually the first acronym used after the words Heidelberg eg: “Heidelberg SM 72V” would mean that the machine in question is a SpeedMaster, similarly “Heidelberg MO-V” would mean that machine in question is a MO series Heidelberg machine.