Insulation testers are specialized electrical testing devices used to measure the resistance of insulation materials in wires, cables, and electrical equipment. These testers apply high voltage to detect leaks, degradation, or faults in insulation, ensuring safety and compliance with industry standards. Commonly used in industrial maintenance, power distribution, and manufacturing, they help prevent electrical failures and hazards. Features include adjustable test voltages, digital displays, and rugged designs for field use. Popular models include megohmmeters and dielectric testers, catering to applications like transformer testing, motor diagnostics, and HVAC system inspections.