This module can detect very low radiation doses (try the bananas!), so don't panic if it starts clicking. Also you can use it for different purposes, not only the radiation measurements - Geiger counter is a good random number generator, and undetermined high-energy particle ionization events can provide enough random entropy to get you a truly random number, rather than a fixed random sequence based on a random algorithm. Read carefully the instructions on manufactorer's Wiki page before use.

Important notes:
- This product is not a professional measuring instrument, it is only suitable for principle research and teaching demonstration. Not for use in radiation dose measurement that directly affects personal safety.
- Geiger tube is fragile, please handle with care when using.
- The Geiger counter can only detect ionizing radiation, such as nuclear radiation, X-rays, cosmic rays, etc. Unable to detect electromagnetic radiation, such as microwave oven radiation, mobile phone radiation, WiFi radiation, induction cooker radiation.
- M4011 Geiger tube can detect α rays, β rays, γ rays. Among them, hard β rays and γ rays can be quantitatively measured.
- Exposure to strong light may cause high readings on the Geiger counter, please avoid direct sunlight on the Geiger tube.
- The Geiger tube is driven by a voltage of up to 400V, after powering on do not touch the high voltage circuit near the positive pole of the Geiger tube.

Specifications:
- Supply voltage: 3.3V ~ 5V
- Signal output: digital output, pull down when a pulse is detected
- Driving voltage: ≈400V
- Maximum range: 1200 μSv/h (theoretical value)
- Dimensions: 107mm × 42mm

Wiki page