This standard is limited to strip-wound cut cores, in both single-phase and three-phase forms of construction, having rectangular cross-sections and rectangular windows (coil spaces), manufactured from cold-reduced grain-oriented silicon-iron alloy strip, and for use in transformers and inductors for telecommunication equipment and for electronic devices. This standard may be generally applied to cores of other than rectangular window or crosssection. In this case, certain characteristics, e. g. electrical properties and dimensional tolerances shall be the subject of special agreement between user and manufacturer.