Measures altitude, up to 15,000 ft., and barometric pressure. Perfect for use as a navigation aid, or to guide you along contour lines. Includes weather trend indicator (shows if weather is improving or worsening). 202 comes with a softside carrying case and lanyard. 203 comes with rugged ABS polymer hardside carrying case and lanyard. Size: 2.3" diameter x 1.0"D, Weight: 1.4 oz.