Do you wish to constantly monitor ambient radiation levels in your home or office and display them in an easy to understand attractive display? The illuminator displays increasing levels of radiation in 5 steps on a large display that can be viewed from great distances. Normal background radiation levels are indicated by a bright red circle made up of 9 brilliant red LEDs (even in direct sunlight). As the ambient radiation level increases another band of brilliant yellow LEDs illuminate. Finally if radiation levels max out the illuminator (about 20 clicks per second), the illuminator lights up an outer orange-red band of LEDs, indicating that radiation levels may be dangerously high in your location. The illuminator contains a built in speaker to produce the familiar clicks of a Geiger counter (can be disabled if desired). Operates on standard 120VAC or from a 9V battery (not included) in emergency situations if no AC is available. Overall size 8" x 10" x 1.2" thick. Completely assembled -just hang by hook and plug adapter into wall outlet.