Firefly is a precision wind detection instrument designed to give hunters an accurate reading of wind/thermal direction. Firefly takes 512 readings per second, analyzes these readings, and after 3 seconds, reports the results in the form of easy-to-interpret LED lights. Operating Firefly is easy-Simply push the button. Fireflly continues to sample and report for 5 more seconds and then automatically turns itself off after 8 seconds of non use. To operate, just remove the protective cap, hold the unit still and level at a comfortable distance away from your body and depress the button. Firefly will continue to sample and indicate the direction the wind is coming FROM each second through 8 seconds, at which time it will turn itself off. Rotate your body 90 degrees and activate the button a second time to take another reading if you think your body may have been blocking the wind drift. The unit is programmed so that if no wind is apparent or there are light swirling drifts and an accurate reading cannot be determined, all LEDs will blink randomly after 8 seconds indicating an Error condition. If this occurs, rotate your body 90 degrees and activate again. It operates on two AAA batteries and has been designed to allow for a minimum of 500 activations with new, fully charged batteries. If the batteries are nearly dead, all LEDs will blink for 5 seconds immediately when the activation button is depressed.