Klein Tools CL390 vs Southwire 21510N

Last updated: November 9, 2026

The Klein Tools CL390 rates 3.7 among AC/DC clamp meters; the Southwire 21510N rates 2.8 among AC only ones. The Southwire 21510N costs $20.46 less ($65.81 vs $86.27).

Prices were last checked November 9, 2026. Product prices and availability are accurate as of that date and are subject to change; the price and availability shown on Amazon or the retailer's site at the time of purchase apply. As an Amazon Associate we earn from qualifying purchases.

Klein Tools CL390 vs Southwire 21510N

Scores side by side

These two sit in different type classes (AC/DC and AC only), and each is scored against the reference points for its own class, so a rating says how well each does among its own type peers. How we rank explains each factor.

Factor weightKlein Tools CL390Southwire 21510N
Overall rating3.7/52.8/5
Current range 15%46 400 A through the jaw46 400 A through the jaw
DC current 15%100 DC current to 400 A through the jaw0 no DC current
Safety rating 20%55 CAT III 600 V55 CAT III 600 V
Features 15%50 true RMS, non-contact voltage, temperature, DC microamps10 non-contact voltage
Accuracy 10%67 2% of reading50 current accuracy not published (neutral score used)
Jaw opening 5%70 41 mm jaw50 jaw opening not published (neutral score used)
Warranty 10%50 2-year warranty0 warranty not published, scored as none
Price 10%76 $86.2788 $65.81

Specifications

Klein Tools CL390Southwire 21510N
Measurement
AC current (jaw)400 A400 A
DC current (jaw)400 ANo
DC microamps (leads)200 uA-
Voltage600 V-
Current accuracy2% of reading-
Jaw opening41 mm-
Safety
CAT ratingCAT III 600 VCAT III 600 V
Features
True RMSYes-
InrushNo-
LoZ modeNo-
Non-contact voltageYesYes
Low-pass filterNo-
TemperatureYes-
Phone appNo-
Build
Weight291 g-
Warranty2 years-

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