Automatic mixer systems are mixing equipment where firefighting water and foam concentrate are pressurized separately from each other as typically used in refineries and storage terminals. This section describes MA, MAP/M and MSC/M type mixers produced by C.S.I. S.r.l. to create accurate foam mixing where needed. This equipment regulates pressurized foam concentrate flow by sensing the water pressure and changing the geometry of the foam concentrate passage. An important thing to know with this kind of equipment is to always have superior pressure at the foam concentrate line with respect to the firefighting water line.