The Circle Safe 778A aerosol included in the fluorescent magnetic particle testing set is used as a magnetic indicator. This aerosol is composed of fluorescent corrosion-inhibitor particles, wetting agents, and pH-value regulators. Circle Safe 778A has been designed to detect very small flaws on finished and untreated parts made of ferromagnetic materials. Most particles (no less than 98%) pass through a standard filter no. 325 (45µm).The color of these particles in UV light is yellowish green. The Circle Safe 850A aerosol, which