Protected in a shock-resistant case, the model SB-500 measures altitude to 16,000 feet in 100 foot increments. The clear and easy-to-read dial can be calibrated to known elevations by simply turning the outside dial. Barometric pressure between 21 inches of mercury and 31 inches is measured on the inner ring. The altimeter is protected in a soft, vinyl case with a clear window. Comes with lanyard.