This CID covers two types of heaters of 28 volt(V) direct current(dc) nominal
rating. used for heating crew and engine compartments of military vehicles or equipment. Type I
heaters are intended for use on military vehicles or equipment which may be required to operate in
an ambient temperature to minus 65 degrees Fahrenheit(-65°F); from which a supply of gasoline
is available; when heated air is required without the vehicle engine being operated. Type II
heaters are intended for use on military vehicles or equipment from which a supply of heated
circulating liquid(engine coolant) is available, which may be required to operate in an ambient
temperature to -25°F.