FD-90A-H2S

i have never heard it beep, even though i really tried. I was told one needs to buy an extra probe to make it work. I havent tried that yet

Very impressed with the performance and accuracy of this monitor. One of the few at this price level that gives real time ppm readings along with alert level notifications. Only downside, it's a little bulky, but the performance offsets that minor issue.

Rechargeable battery went dead (would not charge) just after the one year warranty expired. ***UPDATE 10/11/19*** I contacted the company I ordered from and told them what happened and they replaced the unit even though it was a bit out of warranty. The new one is working great. I am happy.

Came ready to use. So glad it worked my husband was in a poisonous gas area and unit went off. I like it is rechargable.

Very well built, easy to use, rechargeable, pick up on very small readings, self calibrates. I am very happy with this meter for the price.

This sounds great. Low price point, and a lower detection level than some devices triple the price, what could be wrong!? Well, if it's too good to be true, then it's probably not true. There are no EPA approved devices that can detect lower than 1ppm, yet this claims to detect .1ppm. Let me tell you, we had a professional test done which showed the H2S presence. Then, we busted the concrete, took apart and left the pipes open. If you've ever smelled H2S, it's unmistakable. Smells like rotten eggs, with a hint of difference. So we have the pipes open, we can smell it strongly, a professional grade device is alerting us, and this thing sits there happily, saying there's zero H2S in the air. Put it into the enclosed tank - still reads zero. It's been calibrated, doesn't matter. Maybe if I tossed it into some pure H2S it would detect it, but that's not the point of the detector, is it? If you have a good reason to suspect H2S in your home or office, DO NOT USE THIS. As you can see with many other reviews, you'll use it and think you're fine. You'll have peace of mind believing your space is safe. But you may be wrong, trusting the device that can't detect low levels of the gas. Even professional grade handheld detectors that cost ten times this amount do not reliably detect below 1ppm, but chronic exposure affects humans at far less than 1ppm! If you need a detector for on the job, then you're in a place that is known to have an H2S exposure risk. Don't cheap out. Your health is on the line. Go with a professional model if you need it for professional use.