The GMC 320 Plus (V4) is a hugely popular pocket Geiger Counters, and it comes with a FREE rugged waterproof storage case. It has all of the key features of its predecessors: excellent sensitivity to β,γ & X-Ray (beta, gamma & X-Ray radiation), compact size, large backlit LCD readout, easy to use, rechargeable battery and PC connectivity, plus a raft of new features that make it even more versatile. These include:


  • Larger flash memory for storing data
  • Improved battery life
  • Built in temperature sensor & gyroscope
  • Faster PC connectivity
  • User replaceable battery
  • Free unlimited data storage/history and Geiger Counter World Map service (V4 via PC, V5 via WiFi). 

Stop Press!

We now have a limited stock of the newest V5 variant of the GMC-320 Plus. This has a built in-Wi-Fi module that allows you to upload logged data directly to GMC’s unique web-based Geiger Counter World Map via a Wi-Fi connection. Your data will be stored and contributes to a fast-growing, crowd-sourced, global radiation monitoring network. You can select the V5 model from the Options box above the Add To Cart button


Both models are brilliant all-rounders, perfect for enthusiasts, schools, students, antique dealers and collectors, urban prospectors, rock hounds, gadget fans, doomsday preppers. In fact anyone who is curious or concerned about their environment. Although the  y are not intended for use in health and safety or safety-critical applications, they're sensitive enough to detect normal background radiation and therefore quickly alert the user to elevated levels. They also makes a great learning aid for schools and colleges


For everyday use both 320 Plus models show a continuous readout in microsieverts per hour (uSv/hr), counts per minute (CPM) or milliroentgen per hour (mR/h). This can be shown as large font digits, a more comprehensive time-relative multi-line text display or as a continuous moving graph.


There's an audible ‘clicker’ and flashing LED blinker plus a user-set alarm beep that sounds when the count or measurement exceeds a pre-set limit, a built-in real time clock, used to time-stamp data, logged at second, minute or hourly intervals and it can store several days worth of readings and user set data (note, location etc.) on its one megabyte internal flash memory. The display auto rotates, so it can be mounted or used inverted, and there’s a standard mini USB port on the side, along with a 3.5mm jack socket for connection to headphones or an amplifier etc.


Both GMC-320 Plus models can communicate with PCs running Windows (XP onwards) or Linux operating systems. The data link can be used to provide a real-time numeric and graphical display on a computer or laptop screen using free data/history viewer software. You can also use it to download (and play back) data from the GMC-320Plus stored on your PC. The software features improved PC connectivity and also includes a brand new feature for automatically uploading data to a website called The Geiger Counter World Map (www.gmcmap.com  where readings and data collected from GMC users around the world are now being displayed.


Okay, that was the quick tour; there’s lots more but, for tech heads, here are the key specs and features at a glance:


  • Radiation types detected: Beta and Gamma & X-Ray
  • Gamma Sensitivity: 0.1~3.0 MeV
  • M4011 Geiger Muller tube
  • Max count: 65,235 cpm
  • Three points calibration, CPM to uSv/h and mR/ h conversion
  • On screen menus
  • Graphic zoom
  • Audio, battery status, alarm, data save indicators
  • Switchable audio & alarm options
  • Alarm range 0.01 – 10.00 uSv/0001 – 9999 cpm
  • Real-time clock
  • On-board temperature sensor
  • On-board electronic gyroscope
  • Internal flash memory for data logging
  • Data recording by second, minute or hour
  • User settable location/note facility
  • History data searching
  • Dimensions: 124 x 73 x 24mm (5 x 2.85 x 1 in.)
  • Weight: 168g (6oz)
  • Working Voltage: 3.2-4.0V
  • LCD Display: Dot matrix with back light
  • Working power: 0.045W - 0.2W
  • Power: 3.6V/3.7V battery / USB power
  • User replaceable battery
  • Built-in battery charging circuit
  • Power saving mode

To hear it in action and sound alarm click HERE


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GMC-320 Plus Pocket Geiger Counter with FREE Waterproof Storage Case - More V5s arriving shortly!

  • Product Code: GMC-320 Plus
  • Availability: In Stock
  • £129.00


Available Options