Milli- and micro-ohmmeters send voltage pulses through parts and equipment to detect electrical resistance levels below a single ohm to identify insulation leaks and shorts. Also called low-resistance ohmmeters, these portable, compact instruments use four test leads to contact test objects and help electricians, operators, and facility maintenance crews identify and diagnose problems and prevent permanent damage to electrical systems. They are often used for indoor or outdoor testing of circuit breakers, ground bonds, motors, coils, and switches. Additional uses include testing applications in chemical plants, mines, railroads, telecommunications, and automotive and aircraft industries.