The free Physics Toolbox Magnetometer is a simple app that allows you to measure and display the magnetic field (EMF) in the earth's environment. 

It is a useful tool for a wide range of educational and scientific applications. It can be used in a variety of ways. For instance, it is a good tool for teachers to use in the classroom to demonstrate the principles of magnetic field and magnetism. It is also a good tool for the investigation of the magnetic field in nature.

It is a simple app that is easy to use. It does not have any complicated settings or options. You just need to tap on the screen to start the measurement.