H2S Gas Detector, Portable Hydrogen Sulfide Detector Gas Leak Detectors & Alarms Electrochemical H2S Monitor Meter Single Gas H₂S Sensor Poisoning Alarm with Clip and LCD Screen Backlight

Seems to do the job.

The instructions seem simple at first but then they just end with no instructions what to do next. I tried several different things but still couldn't figure it out.

Does not work. New batteries 2 sets. Turns on 2min later it’s off again. Turn on again back off. I sure hope I’m not in h2s situation with this I’d be dead.

Thankfully, I don't know if it works or not. That's a good thing. However, there's no belt clip. I had to cut the clip off an old neoprene IWB holster and gorilla glue it to the back of this to have a clip. Of course that means I can never change the batteries, but let's face it, if you're buying this is because you're starting a job in the oil and gas industry and you're low on cash. The way I look at it, by the time the batteries die, I can afford a more expensive model (with a belt clip).

Easy to use and calibrate

Not sure where at home you would use this but, really not a product for a world of poisonous gas. It’s not for personal use. No clips or anyway to carry it on your self. It takes regular aaa batteries. Not sure how long they last yet. It appears to turn off on it’s own after 10 min. I guess it knows when you are done? Was not what I was looking for.