Klein Tools ET310 Digital Circuit Breaker Finder
A two-part tester: plug the transmitter into an outlet, scan the panel with the receiver, and it beeps and lights at the matching breaker. The transmitter also tests the outlet's wiring and GFCI.
Quick verdict
Yes, if you need to match outlets to breakers or label an unlabeled panel. With the Klein ET310 you plug the transmitter into an outlet and scan the panel with the receiver, which beeps and lights at the matching breaker; the transmitter also checks the outlet's wiring and GFCI. It can't find 240V breakers and doesn't read voltage.
- Best for:
- Finding the breaker for an outlet.
- Watch out:
- 120V only; no 240V breakers.
Amazon US listing and availability checked October 27, 2026. Prices and stock can change.
Reviewed October 25, 2026 · How we review
Part of our buying guide: Hand Tool Gifts: How to Pick One They'll Use, Not One They Already Own
Our Take
Unlabeled breaker panels turn simple jobs into guesswork, and switching breakers off one by one cuts power to the rest of the house. The ET310 finds the right breaker first. You plug the transmitter into the outlet, then run the receiver over the breakers; Klein says it gives visual and audible signals at the right one. The transmitter is powered by the circuit and also checks the outlet's wiring and tests GFCI outlets. It works on 90–120V AC circuits with North American grounded outlets, so it won't find 240V dryer or range breakers. Light fixtures and bare wires need Klein's 69411 accessory kit, sold separately. The receiver runs on one 9V battery (included), switches off after about three minutes, and Klein rates the tool for a 6.6-foot drop. It's CAT II rated for outlets, not for testing inside the panel. We haven't tested it ourselves.
Specs (This Configuration)
- Circuits
- 90–120V AC, North American grounded outlets (Klein)
- Parts
- Transmitter (with GFCI outlet tester) and receiver (Klein)
- Battery
- One 9V in the receiver, included; transmitter powered by the circuit (Klein)
- Durability
- 6.6 ft (2 m) drop; CAT II 120V (Klein)
- Fixtures
- Needs accessory kit 69411, sold separately (Klein)
- Weight
- 7.2 oz (Klein)
Best For
- Labeling an unlabeled breaker panel
- Turning off one circuit before replacing an outlet or switch
- Quick outlet wiring and GFCI checks
Skip If
- You need to find 240V breakers (dryer, range, AC)
- You're outside North America
- You need a meter for voltage readings
What We Like
- Finds the breaker without switching others off
- Outlet wiring and GFCI tester built in
- Transmitter docks in the receiver for storage
What To Know
- 120V circuits only
- Light fixtures need the separate 69411 kit
- Amazon may share ratings with Klein's ET310 kit on the same listing
- Our photo is Klein's press image from the product's 2019 launch
Pros
- Sold by Amazon.com on the listing we checked
- 9V battery included
- Rated for a 6.6-foot drop
Cons
- Not for 240V breakers
- Accessories cost extra
- No voltage readout
Alternatives
No direct alternative we've reviewed; these go with it for outlet and switch jobs.
- Klein Tools 11055 Wire Stripper and Cutter — Once the breaker is off, the stripper you'll want for replacing an outlet or switch.
- Klein Tools 32307 27-in-1 Tamperproof Screwdriver — A multi-bit screwdriver for cover plates, outlet screws and the odd security screw.
Why PriceDropIQ Selected It
If your panel labels are missing or wrong, finding the breaker for one outlet usually means flipping breakers until the radio goes quiet. The ET310 points to the right breaker while everything else stays on, and checks the outlet's wiring while it's plugged in. It suits homeowners and DIYers working on 120V outlets; it won't find 240V appliance breakers.
Before You Buy
- Check the title says ET310 (the ET310KIT adds accessories)
- Check your circuits are 120V, North American outlets
- For light fixtures, check you also have Klein's 69411 kit
Frequently Asked Questions
Can it find breakers for light fixtures?
Yes, with Klein's 69411 accessory kit, sold separately, which connects the transmitter to fixtures and other wiring.
Does it work on 240V circuits?
No. Klein lists it for 90–120V AC circuits only, so it won't find breakers for 240V dryers, ranges or air conditioners.
What battery does it use?
The receiver uses one 9V battery, which Klein includes. The transmitter takes its power from the outlet.
Related Buying Guide
More in Tools
All Tools reviews and guides
Interested in this product?
Reviewed October 25, 2026. Check the current offer, seller, availability, and shipping details on Amazon.
Independent buying advice, in your inbox.
New reviews and practical buying guides from PriceDropIQ.