The Radalert HAC001 is a general purpose geiger counter that measures alpha, beta, gamma, and X-radiation. Exciting new features of the Radalert 100™ (which is the upgraded version of the popular Radalert 50™), include a three-second update and a utility menu that allows you to change the default settings for several operating parameters. Its digital liquid crystal display (LCD) shows the current radiation level in your choice of milliroentgens per hour from .001 to 110 or counts per minute (cpm) from 0 to 350,000. When SI units are selected, the LCD shows readings in microsieverts per hour from .01 to 1100 or counts per second (cps) from 0 to 3,500. This instrument also offers an accumulated total and timer function, up to 9,999,000 counts and 40 hours.