Geiger Counter Nuclear Radiation Detector - FNIRSI Radiation Dosimeter with LCD Display, Portable Handheld Beta Gamma X-ray Rechargeable Radiation Monitor Meter, 5 Dosage Units Switched

Seems to work very well, is easy to read, robust, and portable. Durable in case of a situation like in the movie The Road.

Works. As soon as I turned it on it started measuring background radiation in the 0.02 to 0.11 uSv/h. But I couldn’t really tell if it was working or not or just measuring some kind of noise.So I drove to work and back home and walked around at work but nothing triggered a higher reading.So I took it to a lab where they have Cobalt 60 readily available for radiation testing and just walking into the outside room behind the multiple feet of lead and concrete my meter went from 0.01 to 1.0uSV/h in just a few seconds. The little red light at the top wasn’t flashing anymore, it was solid red. So I knew that meant it was measuring the radiation and it was tripping an alarm to let me know I was way over the 1uSv/h alarm limit.That was good enough for me.On another note, the menu system is a little kludgy and you cannot save a screenshot or any history which is kinda disappointing, but for a quick measurement for on the spot radiation testing, I would say it does what it promises. I. Just wish it would connect to my phone through Bluetooth so I can download the data to save for later.

EDIT - After leaving this review, I was offered a full refund by the seller. In light of this, it's clear they stand by the product and I received an unlucky unit. I'll leave the written portion as is below, but the rating is getting a big bump. For a $70 Geiger counter, so long as you don't get unlucky, it gets the job done. If you do get unlucky, turns out customer service is great.OLD REVIEW - Bought in late June 2023, as of writing this (early May 2024), it is no longer functioning. It is visibly in mint condition, yet has decided to stop functioning. It lasted less than a year, used maybe 10 times.It now just stays on the boot screen, vibrating and beeping for a while till it gives up (10 minutes? I haven't tested it, the beep is annoying so I put it out in the garage till it shuts up). Tried the reset button (right of the charge port), pulled it apart and disconnected both batteries for 30 minutes, even tried a YouTube comment guiding me blindly through a menu reset in case just the display was bugged. Nothing has fixed it and when googled, it seems like this is really not that rare of an issue.Even when working, accuracy is all over the place bouncing from 0.00 to 0.50+ microsieverts even when held in place. The display is okay, nothing crazy but also not bad. The feel of the product is of decent quality as in, it doesn't feel as though it would break if I dropped it a few times (although it seems to just break on it's own anyways, so the quality feel is a bit of a moot point).

Before I begin, I need to say that this is a Geiger counter that has been designed to be a dosimeter. It measures the accumulated radiation exposure in fractional units of Sieverts over time. This is a high quality dosimeter considering the price. It can read gamma, beta and x-radiation dosages. Two screens are provided: the first is numerical and the second is graphical. The manufacturing quality of this instrument is evident at first glance. It is beautifully packaged in order to protect the Geiger-Mueller tube in shipping which is otherwise subject to shock breakage. I purchased this item in order to monitor radiation dosages in two places in my home. The first is an activated charcoal filter that I have on my water supply in the basement while the second is a reverse osmosis system with charcoal filters under the kitchen sink. Since there is radon in my well water supply, I prefer to remove as much as possible before it is delivered to the faucets in the house. It also serves to reduce the radon levels in air due to cooking, washing, showering and laundry. Capturing the radon in activated charcoal will also capture radon decay products (daughter products). Some of these have very short lifetimes, but some are extremely long and tend to build up in the activated charcoal filters over time. I wanted to see how these radiation dosage levels increased over time in order to determine the optimal time to change the filters. The first thing that I noticed was that in just one week, after a basement filter change, the radiation had already built up by a significant amount. The radon radioactivity in our water is approximately 3000 pCi/L. If allowed to vaporize due to cooking, washing, bathing and laundering, this amount of radiation could add about 0.3 pCi/cubic meter to the air. The radiation dosage level that was measured close to the tank was 1.4 uSv/hr according to the meter. If multiplied by the number of hours in a year, 8760, we arrive at the accumulated dose per year which is 12.3 mSv. This is the amount of radiation exposure that would be possible were a person to stay in proximity to the tank for an entire year. This exceeds the NRC dosage guidelines of 1 mSv (0.1 rem) per year. Clearly, the filter should not be placed anywhere near where people or children would normally gather or play, for example, a finished basement. I will be monitoring the activated charcoal filter tank for several weeks to see if the radiation buildup reaches equilibrium as the filter capacity is exhausted. This will provide a guideline for how often the filter should be replaced. Short term exposure to the filter during a filter change should not be an issue provided that safe handling practices are followed. As a followup, I have decided to change the activated charcoal filter in the basement four times per year since no one is in proximity to the filter most of the time. One additional piece of information: For occasional proximity to radiation by workers, the annual permissible dose is 50 mSv (5 rem) per year. On the subject of radioactivity and dosage; they are not the same, pCi/L cannot be converted to uSv, or vice versa. The first is an instantaneous radiation level in disintegrations per second from a liter of water, while the second is an accumulated exposure dosage over time. Finally, I am not a licensed professional engineer or health physicist. Always consult with a professional engineer or health physicist who is. Most water system installers pose as being knowledgeable, but they are not. While they may attend training courses in radon mitigation, they do not possess the knowledge required to make sound health decisions for your family.