Volume Power is a free Android app from GUANREN that allows the user to unlock their screen using the volume keys. This app is particularly useful for those whose phone power button is broken.

The app works by clicking on the volume power notification bar to lock the screen. Users can then unlock the screen by using the volume keys, which can reduce the use of the power button. It should be noted that this feature is only available for Android versions below 6.0.

However, there are some warnings to consider before using this app. Firstly, the use of the app will increase power consumption, which is unavoidable. Secondly, the app cannot be started or shut down. Lastly, it is not guaranteed to work on all systems as it may be limited by the system.

Overall, if you have a broken power button and an Android system below version 6.0, Volume Power is a great app to consider.