For Precision & Competitive Shooting - The Kestrel with Hornady 4DOF quickly and accurately determines long range holdovers and windage corrections to get you on target with first round hits. This all-in-one unit combines real-time environmental measurements with the 4DOF ballistics calculator for a rugged and dependable compact yet powerful long-range shooting tool. No more DOPE cards guessing at the wind or being unsure where your bullet will hit when you change elevation.Environmental Measures : Altitude (Barometric)Barometric PressureCompass DirectionCrosswindDensity AltitudeDew Point TemperatureHeadwind/TailwindHeat Stress IndexRelative HumidityStation Pressure (Absolute Pressure)TemperatureWet Bulb Temperature (Psychrometric)Wind ChillWind Speed/Air Speed