This SkyScan Model P5-3 Lightning Detector takes the guesswork of of judging the dangers of lightning. Now with the SkyScan, it's just a simple matter of pushing a button. Powered by (6) AA batteries (not included,) this detector will operate approximately 75 continuous hours with full use and approximately 100 continuous hours on battery save mode. The SkyScan P5-3 Lightning Detector is completely self-contained measures 6" x 3" x 1" and requires no installation. The P5-3 is a compact lightning detector that is very reliable, small and sleek. This lightning detector is the newest high technology weather monitoring product available, it is a hand-held instrument with an electronic system to detect the presence of lightning/thunderstorm activity occur. It will pick up electrical activity as far as 40 miles away and track the storm as it approaches giving you plenty of time to clear the jobsite or field, leave the campground, or sail back to shore. Be warned of a approaching storms by an audible tone and by 4 LEDs ranged in miles, 0-3, 3-8, 8-20, 20-40. You can even select the range at which you wish the alarm to sound. This lightning tracking device is an essential safety device for any outdoor worker, sports coach, weather enthusiast, or storm chaser. It uses a patented full digital microprocessor insuring accuracy and reliability to determine the distance of a storm. The instrument detects electromagnetic emissions from individual lightning strokes and can be detected at long range by use of ad hoc sensors. You are at immediate risk any time there is detected lightning activity within 9 miles of your location. Since the lightning detector allows you to know the level of activity of the storm, it determines if it is moving towards, away or parallel to your position. Each time it detects a lightning stroke, it emits an audible warning tone that lights the Range Indicator Column. The full column stays lit for approximately 3 seconds, this feature allows you to see the distance to the last, closest, detected stroke without waiting for the instrument to detect a new stroke. The basis of SkyScan's new and patented technology is that the unit samples and analyzes selected pairs of frequencies within the electromagnetic spectrum of a lightning stroke, it then applies this information to determine the distance of that lightning stroke. The strength and uniqueness of the SkyScan approach is that it allows a tremendous amount of information to be extracted and analyzed by a relatively simple hardware system. The simplicity of the hardware is made possible by the proprietary software, which performs the analysis of the incoming information. The reliance on software, rather than on hardware, also allows the SkyScan system to be extremely intelligent with regard to eliminating false triggering while displaying several different types of important information to the user. The unit is accurate to within 1 to 2 miles 97% of the time and carries a One Year Limited Manufacturer's Warranty. Additionally available accessories for your SkyScan P5-3 Lighting Detector include: A/C Power Adapter (P/N: SKAC) and Wall-Mount Bracket (P/N: SKMB). Accessories sold separately. Detectors sold individually.