Max Altimeter is a free Android app developed by Maxcom that uses GPS to measure the altitude of the device. It is a simple and easy-to-use altimeter that displays the current altitude and elevation change over the past 5 minutes. The app also offers a selectable color theme for the user's preference.

To use the app, the GPS must be enabled and the device must be placed under an open sky to receive the GPS signal. The app is not suitable for indoor use and may cause signal distortion in places such as skyscrapers or wooded areas, resulting in measurement errors. Depending on the surrounding environment, it may take some time for the GPS to initialize.

Overall, Max Altimeter is a useful app for hikers, climbers, and anyone who needs to measure altitude on the go. However, it should not be used for special environments such as skydiving or flying height measurement.