1 / 7Klein Tools RT210 GFCI and AC Outlet Tester
Outlet: The Klein Tools RT210 is a hand-powered plug-in tester for standard and GFCI receptacles. Its indicator lights and printed chart are intended to help identify common wiring conditions, while its GFCI test checks operation of the ground-fault protective device.
At a glance
- Indicates common wiring conditions from its light pattern, with a chart on the tester to help interpret the results.
- Designed to test standard and GFCI receptacles and check GFCI protective-device operation.
- Manufacturer says the unit is built to withstand a 6.6-foot (2m) drop.
Often bought together
Pros and cons
Pros
- Printed light-pattern chart provides an at-a-glance reference when checking receptacles.
- Hand-powered design needs no separate battery for the described outlet tests.
- Compact listed dimensions and low listed weight suit carrying between outlets.
Cons
- Indicates common wiring problems rather than providing the broader measurement functions of a general-purpose electrical meter.
- The manufacturer lists a limited operating range of 110/125V AC in a 3-wire outlet.
Technical specifications
9 specifications| Brand | KLEIN TOOLS |
|---|---|
| Model | RT210 |
| Power configuration | Hand Powered |
|---|---|
| Nominal voltage and frequency | 110/125V AC at 50/60Hz in 3-wire outlet |
| Compatible receptacles | Standard and GFCI Receptacles |
| Specification listed | Cat Ii 300v |
| Operating temperature | 32-Degree to 140-Degree Fahrenheit (0-Degree to 40-Degree Celsius) |
|---|
| Dimensions | 5.3 x 3.8 x 1.5 inches |
|---|---|
| Weight | 1.9 ounces |
What to know before buying
- The listed fault indications include open ground, reverse polarity, open hot, open neutral and hot/ground reversed. The tester's indication is a screening aid and does not establish that an outlet or installation is safe. Follow appropriate electrical procedures.
What’s in the box
Included- GFCI outlet tester
Who is it for?
A good fit for
- DIYers checking common wiring conditions at North American standard and GFCI receptacles.
- Users wanting a compact tester with a printed guide for interpreting indicator lights.
Less suited to
- Buyers who need detailed voltage, current or resistance measurements.
- Users testing receptacles outside the stated 110/125V AC, 50/60Hz, 3-wire application.

Customer reviews on Amazon
- 5 stars
86% 86% - 4 stars
10% 10% - 3 stars
3% 3% - 2 stars
0% 0% - 1 star
1% 1%
Customer feedback describes the tester as easy to use, compact and readable, with reports of useful wiring indications and quick outlet checks. That simplicity aligns with its indicator-light and printed-chart design, which is for common receptacle checks rather than broad electrical measurements. Feedback also raises reliability concerns, including reports of failures after a few months, so longevity may matter to frequent users.
Positive themes
- Customers report convenient operation and clear light-pattern interpretation.
- Customers describe it as compact and useful for DIY outlet checks.
Negative themes
- Some customers report that the tester stopped working after a few months.
Frequently asked questions
What receptacles is the RT210 intended for?
The listing says it works with standard and GFCI receptacles in 3-wire outlets, with nominal voltage stated as 110/125V AC at 50/60Hz.
What wiring conditions can it indicate?
The listing names open ground, reverse polarity, open hot, open neutral and hot/ground reversed. A chart on the tester helps interpret the light pattern.
Does it test a GFCI outlet?
It is designed to check GFCI protective-device operation as well as indicate common wiring problems. The listing does not describe it as a full electrical safety assessment.

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