The altimeter is a valuable tool for mountaineering, backcountry skiing and wilderness travel. Most types of altimeters like the Suunto Core rely on air pressure measurement to determine elevation. That is because atmospheric pressure increases or decreases depending on your elevation - the higher you climb, the lower the air pressure. You can use altimeters like the Suunto Core to establish your current elevation, track ascent or descent and gauge progress on a climb. If you’re on or near an obvious feature (like a ridge or trail), you can use your current elevation to find your position on a topographic map. Further, if you plan on climbing a slope to a predetermined elevation and then traversing, an altimeter can help you stay on course.