Pro Series 3 Radon Detector Radon is a colorless, tasteless, and odorless radioactive gas produced by the breakdown of uranium in the soil. When allowed to accumulate to high levels, it can be hazardous to long-term health. The Surgeon General has warned that radon is the second leading cause of lung cancer in the United States. Only cigarette smoking causes more lung cancer deaths. Radon levels in a home can vary greatly over a one-month period going from safe levels to dangerous levels and back to safe. The EPA currently states that corrective action should be taken if Radon levels exceed 4 pCi/L (4 pico-Curies per liter) on a long-term basis. Radon gas is impossible to detect without the use of sensitive test equipment. The Pro SeriesII Radon Gas Detector is the only radon gas detector on the market designed for use by the homeowner. This detector allows the homeowner to monitor the radon levels in their home by displaying short-term and long-term averages. Compare the Pro Series 3 with the Pro Series: Numeric LED display range of 0 to 999 shows the level of radon gas in pCi/L on a short-term or long-term basis. Short-term readings display the average radon levels over the past 7 days. Long-term readings display the average radon levels since powered-up or last reset with a maximum reading time of 5 years. Audible alarm sounds if the long-term average reaches 4 pCi/L or greater. Samples air continuously with the display updated every hour. A self-test is conducted every 24 hours with an error code displayed if there is a failure. Menu button controls 4 functions. 1. Allows the user to switch between the short-term and long-term display, which is indicated by a green LED illuminated next to the S (short-term) or L (long-term). 2. Allows the user to conduct a manual test of the detector. 3. Allows the user to mute or reactivate the audible alarm if the detector is in an alarm state. 4. Allows the user to clear and reset the memory of the detector to begin new readings. 10’ power cord allows user to locate detector away from walls, windows and doors. One year warranty.