The TurboFlare™ is the best flare made for marking helicopter landing zones. TurboFlare™s are visible from 25 miles away but will not destroy a pilot's night vision at close range. Because of their unusual rotating pattern, TurboFlare™s provide an unmistakable landing zone for a pilot. Even several miles away TurboFlare™s cannot be confused with any other light source. TurboFlare™s were designed to "dig in" to the ground when subjected to rotor wash. Powered by 4 C cell batteries which provide approximately 150 hours of service. The Best Choice for fire departments, rescue crews and helicopter pilots.