SafetySiren Pro4 Series Radon Gas Detector is a State-of-the-Art Technology that provides accurate and reliable continuous radon gas readings to assist the home owner in taking control of their radon gas conditions. All while keeping it Simple, User-Friendly and Worry Free! No need to monitor battery life, No Batteries Required! Your data is stored in memory and will not be lost unlike other radon detectors during any kind of loss of power. No Lab Fees! No Calibration Required! Family Safety Products, Inc. the manufacture of SafetySiren takes pride in providing top-notch customer service. The SafetySiren Pro4 is a one button operation, everything literally at your finger tip! Pro4 displays both weekly and long term average concentration levels, length of measurements, visual and audible alarm with 3 modes to chose from, back light mode for easy viewing of the display, a test function, and a clear option to restart your test instrument. The radon detector has a one year limited manufacturer warranty. It requires no annual calibrations. Life expectancy is estimated at over 10 years in normal home use.