The control and flasher units covered by this specification are intended for use in directional control signal systems and hazard warning systems of military vehicles. This system should not be used for ambient temperatures above 165°F. This specification should not be used for procurement of control units for newly designed vehicles. Control units, for newly designed vehicles, should be self-cancelling by steering wheel rotation in accordance with Federal Motor Vehicle Safety Standards. These units are military unique because they have to operate over an ambient temperature range from - 65°F to 160°F.