MaterialThis multi-functional 4-in-one portable Altimeter, barometer, compass, and Thermometer is made of high-quality metal + ABS material, light weight, overall beautiful, and easy to carry. It is an ideal product for outdoor enthusiasts. Multi-functionAltimeter displays the current altitude, allowing you to know the altitude where you are in time; barometer and thermoometer can help you predict changing conditions, and predict sudden changes in weather by paying close attention to airpressure trends. Help you take the necessary precautions to make your journey safe and successful. Direction guideThis mountaineering hook belt is equipped with a compass, a sensitive and accurate compass, and will never get lost. It adopts special technology to improve sensitivity and accuracy. This beautiful compass will always guide you in the rightdirection. How to useBefore climbing, if the height of the starting point is known, adjust the Altimeter pointer to the scale of the known height. In this case, the measuRED data is the true altitude of the mountain. If you don"t know the height of the startingpoint, adjust the Altimeter"s pointer to zero. In this case, the measuRED data is the relative height of the mountain, that is, the height relative to the starting point. Widely usedThis multifunctional barometer combines the functions of Altimeter, barometer, compass, and thermometer. It is specially used for outdoor sports such as mountaineering, rock climbing, hiking, skiing, etc. It can increase and cultivate the funand motivation brought by outdoor sports.