Detecting radiation with a Geiger-Muller tube | fizzics
Geiger counter - Wikipedia
Geiger Counter Tubes
Handheld Geiger Counter Radiation Detector Meter with External Geiger Tube #TZT | eBay
Pocket radioactivity detector
Geiger Counter, Personal Radiation Detector Nuclear Dosimeter Emf Radiation Meter Nukalert Micro Beta Gamma X Ray Radiation Monitor GM Tube Device Meter for Home Thyrosafe Uranium Survival Gear: Amazon.com: Industrial & Scientific