Apart from the Circle Safe 778A and Circle Safe 850A aerosols that are components of the fluorescent magnetic particle testing set, other magnetic powders, concentrates, and aerosols from Circle Safe, Inc. (USA) can be supplied at a customer’s request. All of these magnetic indicators comply with the requirements of state health rules and regulations. As already noted, visual inspection of an object is a technological operation of magnetic particle testing. In order that a hillock of a fluorescent magnetic powder over a flaw be clearly discernible on the specimen surface, it is exposed to UV irradiation with wavelengths of 300 to 400 nm.