The altimeter displays the current altitude in feet or meters, the difference between current and reference altitude, and graphic altitude history for the past 12 hours. Retains memory of maximum / minimum height reached and of the cumulative vertical ascent/ descent. User-programmable alarm. The barometer displays current barometric pressure in mb/hPa or in. Hg and graphical history for the past 12 hours. A storm alarm alerts user when a storm condition is approaching. °C or °F selectable. Clock features a user-selectable 12- or 24-hour format, month, date, alarm and a stopwatch on an easy-to-read LCD display. Includes wall mount and lanyard. Altimeter Specifications: Range: -1,640´ to +22,965´ (-500m to +7,000m). Resolution: 3´ from -1,640´ to +3,280´/6´ from +3,284´ to +22,965´ (1m from -500m to +1,000m/2m from +1,001m to +7,000m). Accuracy: ±3%. Alarm range: -1,640´ to 22,965´ (-500m to 7,000m). Barometer Specifications: Range: 400 mb/hPa to 1,070 mb/hPa (11.8 in. Hg. to 31.57 in. Hg.). Resolution: 1 mb/hPa (0.03 in. Hg.). Accuracy: ±8 mb (±.236 in. Hg.). Temperature range: -20°C to +70°C (-4°F to 158°F). Temperature resolution: 0.1°C (0.2°F). Temperature accuracy: ±1%. Power: 3V CR-2032 lithium batteries (included) with automatic low battery indicator.