Klein Tools ET120 Combustible Gas Leak Detector

The ET120 detects roughly 50 to 10,000 ppm, based on methane. It runs in two sensitivity modes: High covers about 50 to 1,000 ppm for tracing small leaks, and Low covers about 1,000 to 10,000 ppm so a big leak doesn't peg the meter and hide where it's actually coming from. Five red LEDs and an 85dB tone both ramp up as concentration rises.

That's what the 18 inch flexible gooseneck is for. It holds its shape so you can snake the sensor tip into a joint behind an appliance or under a tank, and it clips onto the meter body for storage so it isn't flopping around in the bag. Overall length with the gooseneck extended is 28.31 inches.

No. The ET120 runs an automatic zero-point calibration every time it powers up, and the LEDs flash during that self-check. It isn't reading gas. Important part: always power it up in air you know is clean. If you switch it on standing over the suspect line, it zeroes itself against that contaminated air and will under-read the leak.

No, and this matters. The ET120 is a leak-locating tool, not personal protective equipment. It won't stand in for a confined-space personal monitor or an area alarm, and it should not be relied on to tell a worker an atmosphere is safe to enter. Use it to find the leak; use rated PPE-class gas monitoring to protect people.

It ships ready to work: detector, 4 AAA batteries, instruction manual and a storage pouch in the box. Replacements are standard AAA cells. An auto power-off kicks in after 10 minutes of non-use so a tech who leaves it switched on in the truck doesn't come back to dead batteries.

Yes. It weighs 13 oz (380 g) with an over-molded grip, and the body measures 2.75 inches high by 1.78 inches wide, so it sits in one hand while the other works the gooseneck or a wrench. Alerts are both visual (five LEDs) and audible at 85dB, which is the part that matters in a noisy mechanical room or a dark crawlspace where you can't watch a screen.

Different jobs. Soap solution confirms a leak at a joint you can already reach and see. The ET120 finds the leak first: you sweep the gooseneck along a run and the LEDs and 85dB tone climb as you get closer, which works on concealed piping, behind appliances, and in areas where you'd never see a bubble form. Most techs carry both, using the detector to narrow it down to a fitting and soap to confirm the exact joint.

Klein Tools ET120 is the full manufacturer part number, sold as a single model with no finish or range options to specify. One SKU covers the whole kit (detector, gooseneck, batteries, pouch), which makes it straightforward to spec across a maintenance fleet or multiple service vans.