The Radlamp 300 looks and operates like a small flashlight until it is pointed at an abnormal source of nuclear radiation. The radiation is detected by a sensitive Geiger tube, causing the flashlight beam to change color from white to red. The simple, intuitive operation of the Radlamp 300 gives first responders a simple tool to rapidly evaluate an accident or crime scene for radioactive threats. The Radlamp 300 is sensitive to alpha, beta, gamma, and x-ray radiation. It operates for 100 hours on a set of two CR123A batteries and is sealed, water resistant, and rugged.