The ATH-40-A tachometer/hourmeter with black stainless steel bezel is a rugged instrument with solid-state circuitry for indication of engine RPM and elapsed engine running time. This model will accept all signal sources: alternator, magnetic pickup or ignition. It is powered by a 12- or 24-volt battery with an operating range of 10-32 VDC. It is equipped with a ring nut for mounting into a standard 3-3/8 in. (86 mm) dash mounting hole. A full 240° sweep of the pointer gives an accurate indication on a large easy-to-read scale, and the dial can be illuminated for night reading. This ATH Series' tachometer indicates engine speed in revolutions per minute (RPM), while the hourmeter records elapsed engine running time when the engine speed is greater than 100 RPM. Calibration has also been improved and is now accomplished with a single push button on the back. Replaces: ATHA-30-12-A (20700183), ATHA-30-24-A (20700207), ATHA-40-12-A (20700221), ATHA-40-A (20700141) and ATHI-40-A (20700231).