Initially this series generally comprises catalogue sections in a standard format, with occasional catalogues and other product literature in different formats. From c. 1930 there is an increasing quantity of material in varying formats alongside the traditional catalogue sections, which gradually reduce in number and cease altogether by c. 1960. There is a general trend from catalogues detailing the full range of products, to booklets and brochures giving information on small groups of products and leaflets on individual items.

This series includes material for Fraser and Chalmers, Osram, Pirelli General, Salford Instruments and other subsidiaries having a long association with GEC and included in GEC's standard catalogues.