Non-destructive testing (NDT) services use test methods to examine an object, material or system without impairing its future usefulness. They specialize in NDT methods such as visual inspection, ultrasonics, or eddy current methods. Non-destructive testing (NDT) services may also use the following processes or technologies: acoustic emission, beta gauge, electromagnetic, magnetic (induction or Barkhausen), magnetic particle system, optical (shearography, holography, or magneto optical, penetrant testing, and radiographic or X-Depending on the method and measurement requirements, non-destructive testing (NDT) services can perform activities off-line in laboratory environments, as well as in continuous production line or field monitoring applications.