chemical products for use in tracing cracks, fissures, defects, and stains in and on surfaces; namely, penetrants, dyes, developers, solvents, and penetrant removers, all of which may be in the form of gases, sprays, aerosol sprays, suspensions, emulsions, powders or solids

Chemical Preparations Consisting of Liquid Suspension of Magnetic Substances for Use in Testing Magnetisable Materials