Southwire 21550T
#8 in AC/DCFull review
A true-RMS AC/DC clamp with handy jobsite touches, for electricians who don’t need inrush or a CAT IV rating.
Amazon $90.57$90.57
The Southwire 21550T rates 3.4 among AC/DC clamp meters; the Klein Tools CL120 rates 3.0 among AC only ones. The Klein Tools CL120 costs $26.68 less ($63.89 vs $90.57).
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 CL120
#7 in AC onlyFull review
An inexpensive AC clamp for homeowners and apprentices who need occasional current and voltage checks.
Amazon $63.89$63.89
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 weight | Southwire 21550T | Klein Tools CL120 |
|---|---|---|
| Overall rating | 3.4/5 | 3.0/5 |
| Current range 15% | 46 400 A through the jaw | 46 400 A through the jaw |
| DC current 15% | 100 DC current to 400 A through the jaw | 0 no DC current |
| Safety rating 20% | 55 CAT III 600 V | 55 CAT III 600 V |
| Features 15% | 45 true RMS, non-contact voltage, temperature | 10 non-contact voltage |
| Accuracy 10% | 50 current accuracy not published (neutral score used) | 67 2% of reading |
| Jaw opening 5% | 50 jaw opening not published (neutral score used) | 70 41 mm jaw |
| Warranty 10% | 0 warranty not published, scored as none | 50 2-year warranty |
| Price 10% | 74 $90.57 | 89 $63.89 |
Specifications
| Southwire 21550T | Klein Tools CL120 | |
|---|---|---|
| Measurement | ||
| AC current (jaw) | 400 A | 400 A |
| DC current (jaw) | 400 A | No |
| Voltage | - | 600 V |
| Current accuracy | - | 2% of reading |
| Jaw opening | - | 41 mm |
| Safety | ||
| CAT rating | CAT III 600 V | CAT III 600 V |
| Features | ||
| True RMS | Yes | No |
| Inrush | - | No |
| LoZ mode | - | No |
| Non-contact voltage | Yes | Yes |
| Low-pass filter | - | No |
| Temperature | Yes | No |
| Phone app | - | No |
| Build | ||
| Weight | - | 313 g |
| Warranty | - | 2 years |