This BIRI-1 radiation monitor is small - really, really small and exceptionally sensitive. It has proved to be hugely popular but nowadays they are hard to find. We thought that was the end of it but thanks to a rare warehouse find we managed to secure a very small number of these increasingly rare instruments, and made them even better!

BIRI-1 was a spin-off from the Chernobyl accident. They were made in the Soviet Union using some of the best military grade components. There’s only one control, an on/off switch on the back. When its miniature Geiger Müller tube detects radioactivity (Beta and Gamma) above a pre-set threshold it emits a beep and the red LED on the top flashes. The rate of beeps and flashes increases with the intensity of the radiation field it is detecting. A simple coded chart - see below - on the back of the case shows normal, elevated and dangerous levels as indicated by the number of bleeps and flashes per minute. Typically you will hear several beeps a minute from normal background radiation.


NEW BIRI-1 Special Edition

We've made a few improvements to the BIRI-1 starting with the power supply. It was originally designed to use rechargeable cells: however, these are no longer made but fortunately it can use two types of modern alkaline button cell.

Our new BIRI-1 Special Edition is fitted with a 3D printed button cell holder that takes two inexpensive and readily available AG13/LR44 alkaline button cells. Alternatively the original holder (included with the outfit) can be easily re-fitted, and used with slightly larger LR9 button cells. They last a little longer than AG13s but they have become expensive and increasingly difficult to find. 


We have also replaced the poorly printed labels on the front and back of the case with smarter and more up to date panels and, more importantly, information about what the beeps and flashes mean and the orientation of the button cells - see below.

There’s more. We’re including a newly revised illustrated English language instruction manual based on a translation of the Russian leaflet, also included along with an original certification document (whilst stocks last). And to keep it safe and ready for action it comes in its own fitted pocket sized waterproof case complete with a detachable neck lanyard.


What the Bleeps and Flashes mean

Less than 12 count/min = Normal Background
12-24 counts/min = 60 – 120 uR/hr
24-60 counts/min = 120 -300 uR/hr
Continuous beep/flash = > 3000uR/hr


Some Useful Facts and Figures

Dimensions: 63 x 36 x 16mm
Weight: 23 grams (50g with batteries)
Power Supply: 2 x 1.5 volt AG13 button cells
Detector: SBM-21 Geiger Müller tube
Detection range: Beta & Gamma, 10 to 3000 uR/h (microRoentgens per hour)
Indicators: audible alarm and LED
Supplied accessories: 2 x modern alkaline button cells, neck lanyard, English Instructions, original Russian instructions and test certificate (whilst stocks last), waterproof carry case, original cell holder

ATTENTION EXISTING BIRI-1 Owners
If you would like to convert your BIRI-1 to use AG13 button cells, we can help. Our exclusive 3D printed cell holder is available for just £3.50, inclusive of UK shipping. Overseas buyers please email for a quote.  

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BIRI-1 SE Special Edition Keychain Radiation Detector

  • Product Code: Biri-1 Waterproof Box
  • Availability: In Stock
  • £99.99


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