Geiger Counter - Digital - Professional - Model # GCA-07W External Wand Probe - ANSI N323A Certification Ready- 0.001 mR/hr Resolution - 1000 mR/hr Range

I purchased a GCA-07W Geiger Counter through Amazon in Dec 2015. The Counter I received was delivered in perfect condition. Well made, easy to set up and use right out of the box. You can have the GCA-07W NRC certified if you feel it necessary. That says a lot about the accuracy of the product. I purchased the Charting Software and USB Driver Disc directly from Images SI Inc. after receiving the GCA-07W. Everything I needed to connect the GCA-07W to my Laptop or PC was included. I've been using mine for the better part of the last 5 months with no problems or issues. Works great and is easy to use. Images SI Inc. is a great vendor to deal with.

When I received my GCA-07W, I was impressed with the quality of the manufacturing of the product.The wand is made of a thick lightweight plastic. The end of the wand has a metal screen that protects delicate mica window of the GM tube but allows alpha particles to reach the GM tube. It also has a friction fit wand cap that is an additional protection for the wand. The wand cap must be removed for detecting alpha radiation. For the detection of beta, x-rays and gamma radiation you can leave the cap on the wand.The front panel of the GCA-07W has toggle switch controls. Everything is clearly labeled. I love the toggle switches. The toggle switches snap into position which makes changing the settings intuitive and easy. These switches are so much better than those crappy membrane switches you see on other models. I hate pressing on a membrane switch and hoping the switch press is detected. In any case, that is something you don’t have to worry about with this Geiger counter.Aside from easy set up, I was even more pleased with its performance.I must also point out the customer service from the company is excellent. I needed a little help getting started with the Geiger counter. I was transferred to a technical support person who helped me understand how to take background radiation readings. I was also guided to the company’s online nuclear experiments. Now, I don’t remember most of the math I learned in school. But their experiment 1, not only teaches you the right way to measure background radiation. It teaches you, using basic math, how to calculate the Mean (average) and Standard Deviation of the background radiation, what this means and why it’s useful. They have a dozen or so experiments up on the web, I plan to work through them all and report back here what I find.The next thing I did with my Geiger counter was start testing some old materials I had lying around. I removed the cap and the Geiger counter picked up alpha radiation from some old radium clock faces I have. Then I checked an orange Fiesta ware plate. In both cases these samples caused the Geiger counter to emit a loud clear clicking that easily gets your attention.I installed the company’s free Geiger graphing software on my computer. I had a compatible USB cable to connect the GCA-07W to my Windows PC computer. I ran a background count for 30 seconds, then I put the wand by the Fiesta ware for 30 seconds. You can see from the picture, on the left side of the screen is normal background. The right side of the screen is the radiation picked up from the Fiesta ware. I have two other Geiger counters and the GCA-07W outperforms them hands down. I would recommend this unit to anyone needing a well-built accurate Geiger Counter.

This unit is easy enough to use but has on major issue. The toggle switches on the front of the unit are quite vulnerable to breakage because they protrude out from the unit and could easily damage the switch if impacted from the side. There are many low-profile toggle switches available for use and would significantly improve the design. I recommend getting the uranium calibration tin to check the unit. I prefer the clicking sound of the older counters over the beeps on this unit.

Best price for performance I've found for the avocational user. Nice item!

Stay away from this vendor.I purchased their GCA-07W geiger counter several months ago for my 12 year old son's science project. It made it mostly through a single 9 volt battery before it failed, registering single ionization events as multiple counts. I confirmed the fault both from display and coincident serial output. It's seriously and obviously wrong in its readings, after a short time of operation.We are up against a deadline for my son's project, so I contacted the vendor for support, hoping to arrange a temporary swap or loan so we could get through the project. The vendor refused, and when we ordered another counter, which we paid for in full, the vendor canceled our order.I also ordered a "crooke's spinthariscope" (ironically named) from the vendor, which never worked, so they are 0 for 2. The seller, after refunding my money for the piece of cardboard and wax paper, told me that he, personally, had never been able to see the flashes of light from the spinthariscope.... and yet sells them anyway. Hence "Crooke's Spinthariscope?"The critical observations about the quality of manufacture of the case and wand in other reviews are generally accurate. Specifically, the tube enclosure appears to be pvc pipe. The screen on the end does appear to be heated and melted onto the pvc pipe. The enclosure is nothing fancy, and does resemble a random "project box" for a kit. The holes appear rough or jig cut, certainly not molded. The box labeling is basically decals. I could generate a better design with a few days of effort and solid printing.Also, some folks out there may have ideas of the device having utility in an actual nuclear event... THIS IS NOT GOING TO SUIT YOUR PURPOSE IN SUCH AN EMERGENCY. It will almost certainly be a brick. The device is semiconductor based and not constructed to survive an electromagnetic event... it's internal electronics would likely fail. As someone who has worked with hardened devices I would tell you, you should plan on this device being dead if it is exposed to such an emergency because of the semiconductors and lack of contiguous conductive shielding/grounding.The Geiger counter did work fine, though, for less than a day's duration of operation in a happy, indoor environment.