The Kearny Fallout Meter (KFM) has everything needed to make and use a radiation measuring device. Accurately measures dose rates from 30 mR/hr (0.03 R/hr) up to 43 R/hr. The KFM has undergone rigorous scientific testing in several laboratories where its accuracy and dependability were confirmed. Including Oak Ridge National Laboratory where it was developed by Cresson H. Kearny, author of Nuclear War Survival Skills. Designed to be assembled by a junior high age student, thousands of KFM's have been built worldwide. This same KFM kit has been endorsed by and listed as the sole source in the latest NWSS edition. It also comes with very detailed construction, operating and testing instructions. Also includes a free (non-working) smoke detector to use as a safe radioactive testing source along with color indicating silica gel. And, it does not require a battery. Great science project, too!