This product integrates an altimeter, barometer, thermometer, and compass into one durable unit. It is constructed from high-quality, tear-resistant materials designed to withstand impacts, pressure, cold, and heat, making it suitable for various harsh environments.The altimeter and barometer feature a built-in sensitive air pressure sensor that measures real-time atmospheric pressure. Since altitude is inversely proportional to atmospheric pressure, the device can measure relative altitude. Once calibrated, it provides accurate real-time altitude readings.Combining barometer, altimeter, thermometer, and compass in a single unit, this device requires no battery or charger. With no need for power maintenance or repairs, it offers robust and reliable performance. Its mechanical operation ensures functionality without electricity, making it an ideal outdoor tool.The barometer helps predict weather changes based on atmospheric pressure trends, allowing users to prepare for upcoming conditions in advance. Its compact, lightweight design and thoughtful construction enhance convenience and portability during outdoor activities.This instrument functions as a combined altimeter, compass, thermometer, and barometer. Designed with a pure mechanical structure, it is eco-friendly and built for outdoor sports such as mountaineering, climbing, and skiing. It serves as a reliable companion for outdoor enthusiasts and a valuable tool for various outdoor adventures.