The ATH-40-A is a rugged, transistorized alternator or magnetick pick up signal analog tachometer/hourmeter with solid-state circuitry for indication of engine RPM. It is equipped with a bracket for mounting into a standard 3-3/8" (86 mm) dash mounting hole, and has a bright 304 stainless steel bezel. This model is powered by a 11-28 VDC battery and is reverse polarity protected. The hourmeter ranges from 0 to 99,999.9 hours in 0.1 increments. A full 270° sweep of the pointer gives an accurate indication on a large easy-to-read scale, ranging from 0 to 4000 rpm. The dial can be illuminated for night reading using through dial lighting. This model is designed to function from pulses generated by an alternator with 4, 8, 12, 14, or 16 poles on the rotor. This UNIT has a BLACK bezel