Profile: Hirtzer & Assocs., Inc. H. J. is a manufacturer of insulated links and safety products. Our products include signal alarms and high voltage test equipment. Our model MPA-II is compact in size, and installed in a space less than 4" square. Encapsulated electronics resist weather, shock, vibration and corrosion. Voltage spike is protected to 150 VDC. dual polarity. These are actuated by back-up light circuit, or switch-on reverse gear mechanism. Our circuit filter provides additional voltage spike protection for all electronic alarms, where spikes may exceed the built-in protection of the alarm. It is useful on electronic forklifts, small hand-operated forklifts, and electric motor-driven graders.