The Suunto Observer is an altimeter, a barometer, and an electronic compass with all the features of a sophisticated watch, in a slightly smaller form factor than other Suunto wrist computers. Watch Features include: Day, dual time, and date, plus three daily alarms and stopwatch Altimeter Specs inclue a 9000 meter range, with adjustable altitude alarm, and 24 hours of logbook memory with ability to store up to 40,000 ft of data. The Suunto Observer features the ability to measure ascent and descent rates between stages with altitude simultaneously all by one button access Barometer Specs: Absolute pressure range 300 - 1 1-hPa/ 9.90 - 32.40 inHg Sea level pressure range 921 - 1080 hPa / 27.25 - 30.80 inHg Resolution 1hPa / 0.05 inHg Temperature compensation Automatic 4-day memory stores pressure information in one hour intervals for the last six hours, then in six hour intervals Temperature range -20 degrees - +60 degrees C / -5 degrees - +140 degrees F Barometer use: unique feature to keep altitude from changing when unit is used as a barometer Barometric trend indicator Compass is accurate to two compass degrees with declination adjustment function to correct the difference between true north and magnetic north - uses global needle. Bearings can be taken in degrees and cardinal points Other Features Electroluminescent backlight Temperature compensation Waterproof to 100m/330 ft Maximum battery life of 18 months Low battery indicator User-replaceable battery Titanium case is strong and lighter than Stainless. Comfortable polymer (synthetic rubber) strap with titanium buckle Approximate dimensions: 1 3/4" in width (44 mm) and 14.5 mm thick