Klein Tools CL490 AC/DC Dual Display Clamp Meter - TRMS Accuracy

In this review the Klein Tools CL490 Dual Display Clamp Meter is examined for electricians, HVAC technicians and serious DIYers who need accurate, portable measurements on the job. The single biggest reason to buy is its combination of True RMS accuracy and a dual, high-visibility display that makes readings easier when working in tight or awkward spaces. The meter pairs clamp-based AC/DC current sensing with full multimeter functions, and ships with test leads and a thermocouple for temperature checks right out of the case.

Key Features

• Dual high-visibility screens: A main front display plus a secondary bottom display give alternative viewing angles so readings remain visible in cramped panels or when the meter is rotated.
• TRMS and auto-ranging: True Root Mean Squared measurement and auto-ranging simplify accurate readings on non-sinusoidal signals and reduce the need for manual range selection.
• Clamp and test-lead versatility: The clamp measures AC/DC current and NCVT while the test leads handle AC/DC voltage, resistance, continuity, frequency and capacitance for complete troubleshooting.
• Backlit reverse-contrast LCD: The backlit, reverse-contrast screen improves viewability in dim conditions and provides clear data during early morning or indoor work.
• Convenient hands-free options: A rear test lead holder and optional magnetic hanger give practical ways to position the meter for hands-free operation on larger jobsites.
• Complete kit: Includes carrying case, test leads with safety caps, thermocouple and batteries so the meter is ready to use after purchase.

Who It's For

The CL490 is aimed at professional tradespeople and advanced DIYers who need a dependable clamp meter with TRMS accuracy for mixed AC and DC systems and motors. Electricians who work inside panels, on HVAC systems or in tight service spaces will appreciate the dual-display design and bright backlight.

Those who only need occasional basic voltage checks or who require ultra-compact pocket meters for light home tasks might find the CL490 more feature-rich and slightly larger than necessary. If continuous logging or advanced data export is essential, a different meter with dedicated logging features would be a better fit.

Pros & Cons

Pros

• Excellent measurement versatility with clamp and test-lead functions covering current, voltage, resistance, capacitance and temperature.
• Clear visibility in low light thanks to backlit reverse-contrast displays and a helpful secondary display for awkward angles.
• Accurate readings with auto-ranging and TRMS technology for real-world electrical signals.

Cons

• The main display can be difficult to read in bright sunlight, a common limitation noted by users.
• Auto-power off is useful for battery life but can interrupt long troubleshooting sessions if not disabled.

Specifications

Model	CL490 Dual Display Clamp Meter
Functions	AC/DC current, AC/DC voltage, resistance, continuity, frequency, capacitance, temperature, diode test, NCVT
Accuracy tech	True RMS (TRMS), auto-ranging
Display	Backlit reverse-contrast LCD with dual screens
Included accessories	Carrying case, test leads with safety caps, thermocouple, 2 x AA batteries
Safety / holders	Test lead holder on back; optional magnetic hanger available separately

Our Verdict

The CL490 is a practical, well-rounded clamp meter that delivers accurate TRMS readings and real-world convenience with its dual displays and full multimeter feature set. Professionals who need reliable accuracy, visibility in tight spaces and a ready-to-use kit will find strong value here, while casual users may not need the full feature list.

Frequently Asked Questions

Does this clamp meter measure DC current?
Yes. The CL490 measures both AC and DC current with the clamp and offers NCVT detection for live AC sensing.

Is temperature measurement included?
Yes. A thermocouple is included and the meter can display temperature readings via the thermocouple input.

Can the meter hold readings for later viewing?
Yes. The CL490 includes Data Hold and Max/Min functions to capture and review measurements, plus Rel/Zero for differential checks.