Now you can be aware of radiation levels around you and detect radioactive items anywhere. Our Pocket Geiger Counter is fully assembled, and small enough to fit in a shirt pocket. It operates on one 9V battery (included) and is ready to go. Just push the on/off switch to the on position and radioactive rays of beta and gamma will be indicated by bright red LED flashes and clicks from the speaker. Here in Arizona our background radiation is several clicks per minute, however on a recent flight, the background radiation level was 40 clicks per minute. Old lantern mantles, radium watches, many orange glazed plates from the early 60's cause the Pocket Geiger Counter to chirp rapidly. Size 4" x 2".