Klein Tools CL390 is an automatically ranging true root mean squared (TRMS) digital clamp meter. It measures AC/DC current and NCVT via the clamp, AC/DC voltage, DC microamps, resistance, continuity, frequency, capacitance, and diodes via test leads, and temperature via a thermocouple probe. It features a high visibility, reverse contrast LCD display that optimizes view ability both in dark or bright ambient lighting. For more than 160 years, Klein Tools has manufactured premium-quality, professional-grade hand tools that deliver the performance, durability and precision needed to get the job done right. Our family of engineers, workers and craftsman continue to put six generations of expertise into every tool we create by using only the highest quality materials, superior workmanship, and keeping manufacturing as close to home as we can. Klein isn't just the name of our company, it's also our family name. And since we're an American company that's family-owned and family-run, you know you can count on us to be here tomorrow. Klein Tools doesn't just make great products, we make great products that stand up to the demands of the professionals who use them every day ... Since 1857. VERSATILE CLAMP METER: Measures AC/DC current and NCVT via clamp; AC/DC voltage, resistance, continuity, frequency/duty cycle, DC microamps, diode test and capacitance via test-leads; temperature via thermocouple NON-CONTACT VOLTAGE TESTING: Integrated into the clamp jaw for convenient electrical testing REVERSE-CONTRAST DISPLAY: High-visibility reverse-contrast LCD ensures improved viewability in all lighting conditions ACCURATE MEASUREMENTS: Auto-ranging and True Root Mean Squared (TRMS) technology provides precise and accurate measurements CONVENIENT FEATURES: Test lead holder on the side of the clamp and optional magnetic hanger (Cat. Nos. 69445 or 69417) for hands-free operation ADDITIONAL FEATURES: Max/Min, Rel/Zero, Data Hold capability for enhanced functionality and auto-power off after 10 minutes to conserve battery life COMPLETE PACKAGE: Includes carrying case, test leads with CAT III/CAT IV safety caps, thermocouple, instructions, and 3 x AAA batteries