Use the Vernier Radiation Monitor to explore radiation statistics, measure the rate of nuclear decay, and monitor radon progeny. This easy-to-use sensor consists of a Geiger-Mueller tube mounted in a small, rugged, plastic case. A thin window protected by a metal screen allows alpha radiation to be detected, along with beta and gamma. Each new detection is indicated by a flashing red LED light and can also include an optional audio signal. This sensor requires no battery and is powered by the data-collection interface.