The Kestrel 5700 Elite Weather Meter with Applied Ballistics is a comprehensive weather meter for measurement and logging of primary environmental conditions, including wind speed and direction, temperature, humidity, heat index, pressure, and altitude. It also contains a powerful ballistics calculator to help you hit your long-range shot on the first try. This meter employs the Applied Ballistics bullet library of custom drag models, an exact measurement of your bullet's drag profile plus corrections for Aerodynamic Jump, Spin Drift, Coriolis, and Drop Scale Factoring to achieve accurate extended long-range shots. Features: Bluetooth LINK to Smartphones/Mobile/Android/IOS Takes 1 AA battery (instead of 2 AAA) Battery door is in the back, sealed away from the motherboard, should your battery leak as was common with all the 4000 series Improved high resolution screen for any lighting (even sunlight) and easy on your eyes Intuitive user-interface screen navigation