This is a small-sized Chinese-made glass modern GM tube, sensitive to both Gamma and Beta radiation. The inside of the glass tube is being used as the “cathode.” This was made possible by a process called CVD (chemical vapor deposition) whereby metal material is first vaporized and then deposited on the inner glass of the tube as a conductive metal film; in this case, the film becomes the conductive metal cathode for the Geiger tube. This modern style cathode improves sensitivity, reduces overall weight, and generally decreases complexity, which has helped to keep the cost of this tube low. The ends are capped so that it will easily snap into a circuit designed with snap-in clips. This tube is very sensitive and is perfect for small handheld portable devices needing high sensitivity to beta and gamma radiation.