It is mainly used in aircraft engine oil and helicopter gearbox chip detection systems.
Chip Detectors consist of small plugs which can be installed in an engine oil filter, oil sump or aircraft drivetrain gear boxes.
Magnetic lines of force attract ferrous particles.
Thus, a warning light on the instrument panel illuminates, indicating the presence of metal chips.
[1] Chip detectors may be positioned in the application with a self-closing valve/adapter through either a bayonet or threaded interface.