These bench type equipments often incorporate a canopy to prevent direct light
falling on the subject so that ultra-violet fluorescent material can be used to the best
effect. The indicating particles may be suspended in very thin oil (kerosene) or
water. In some circumstances the indicating medium can be applied dry.
These equipments are suited to production work and in certain circumstances can be
automated to the extent of loading, magnetising, inking and unloading. The work
pieces still have to be viewed by eye for defect indications.
Specialised equipments are also frequently manufactured to test a particular size and
type of test piece.