The Supco M501 electronic megohmmeter is an insulation tester with a 1,000V test voltage for measuring insulation resistance to 1,000MO to indicate the condition of windings or cables in motors, switchgears, electrical installations, and other insulated equipment. The meter displays readings on a zone-type scale that indicates bad, caution, or good insulation condition. It is built into a hard-shell case for portability and protection. The unit comes with a set of test leads and instructions. Megohmmeters are commonly used for electrical maintenance and testing in industries such as HVAC, transportation, manufacturing, mining, and utilities, among others. Specifications Maximum insulation resistance measured1,000MOTest voltage1,000VPower(2) D batteries (sold separately)Weight1.8 lb.Dimensions (H x W x D)*9.25 x 6.5 x 3 inches*H is height, the vertical distance from the lowest to highest point; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back .Megohmmeters, also called insulation testers, are electrical test meters that measure resistance to the flow of current in an electrical component or circuit and check the continuity of an electrical circuit to detect electrical problems such as degraded insulation and improper circuit connections in equipment, wiring, and power supplies. Resistance is an indicator of the overall condition of the device being tested. Megohmmeters have an internal power supply, such as a battery or a capacitor, which supplies a test voltage to a circuit or component that is turned off. Test leads are connected in a series to the tester and the circuit or device being tested. The meter calculates the difference in voltage between the leads and measures the resistance. Most megohmmeters have two terminals for test lead attachment. The two-terminal, or two-wire, measurement method includes the resistance of the circuit or device being tested and the resistance of the test leads, and generally provides sufficient accuracy for measuring large values of resistance in insulation testing applications.Supco manufactures test instruments and replacement parts for heating, ventilation, air conditioning, and refrigeration systems. The company, founded in 1945, is headquartered in Allenwood, NJ. Whats in the Box? Supco M501 electronic megohmmeter Set of test leads Instructions