Defines the grades of thin non-oriented magnetic steel strip in nominal thicknesses of 0,05 mm, 0,10 mm, 0,15 mm and 0,20 mm, and of thin oriented magnetic steel strip in nominal thicknesses of 0,05 mm, 0,10 mm and 0,15 mm for the construction of magnetic circuits used for frequencies equal to or higher than 100 Hz. It gives general requirements, magnetic properties, geometric characteristics and tolerances, technological characteristics, as well as inspection procedures.