The Fluke 1503 and 1508 are cost-effective portable digital megohmmeters designed for routine preventive insulation testing of low-voltage electrical systems. Both models integrate safety features including live circuit lockout, automatic capacitive discharge and 200 mA high-current continuity test, which automatically dissipate residual high voltage after measurement to eliminate on-site electric shock hazards. The 1503 only provides 500 V / 1000 V two test voltages for basic motor and cable inspection. The upgraded 1508 covers five standard test voltages from 50 V to 1000 V, supports DAR & PI insulation aging analysis, data storage and custom pass/fail threshold judgment, with measurement range extended to 10 GΩ to accurately detect minor insulation degradation, ideal for third-party labs and factory outgoing inspection requiring standardized test reports. Compact and lightweight with stable performance over wide temperature range, supplied with remote probe to simplify operation in tight spaces