Extech MA440 vs Southwire 21510N

Last updated: November 9, 2026

The Extech MA440 is the better clamp meter overall, rated 3.1 to 2.8. The Extech MA440 leads on features. The Southwire 21510N costs $1.18 less ($65.81 vs $66.99).

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.

Extech MA440 vs Southwire 21510N

Which should you buy?

Scores side by side

Each factor is scored 0-100 against the same fixed reference points for every AC only clamp meter; a clear win is highlighted. How we rank explains each one.

Factor weightExtech MA440Southwire 21510N
Overall rating3.1/52.8/5
Current range 15%46 400 A through the jaw46 400 A through the jaw
DC current 15%0 no DC current0 no DC current
Safety rating 20%55 CAT III 600 V55 CAT III 600 V
Features 15%35 true RMS, non-contact voltage10 non-contact voltage
Accuracy 10%67 2% of reading50 current accuracy not published (neutral score used)
Jaw opening 5%33 30 mm jaw50 jaw opening not published (neutral score used)
Warranty 10%50 2-year warranty0 warranty not published, scored as none
Price 10%87 $66.9988 $65.81

Specifications

Extech MA440Southwire 21510N
Measurement
AC current (jaw)400 A400 A
DC current (jaw)NoNo
Current accuracy2% of reading-
Jaw opening30 mm-
Safety
CAT ratingCAT III 600 VCAT III 600 V
Features
True RMSYes-
InrushNo-
LoZ modeNo-
Non-contact voltageYesYes
Low-pass filterNo-
TemperatureNo-
Phone appNo-
Build
Weight265 g-
Warranty2 years-

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