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 Pressure Compass Direction Crosswind Density Altitude Dew Point Temperature Headwind/Tailwind Heat Stress Index Relative Humidity Station Pressure (Absolute Pressure) Temperature Wet Bulb Temperature (Psychrometric) Wind Chill Wind Speed/Air Speed