Ordinary exploded mines or mines can only be in contact with the target, and once to add the magnetic sensor, you can in the target of close to but not in contact with (for steel manufacturing objects such as tanks or warships) magnetic field detected when triggering a mine or mine explosions, greatly improving the lethality.
Aircraft in flight are easy to detect by enemy radar in the process, in order to avoid enemy radar monitoring, in airplanes that is coated with a special material (absorber) to absorb electromagnetic waves transmitting, so only a small amount of electromagnetic wave propagation in plane surface reflection, enemy radar radar echoes cannot be detected, unable to find the plane, allowing aircraft to achieve the purpose of stealth.