A. This book has several purposes, some of which are: (a) to obtain the names of companies which are able to provide products bearing a Listing mark or Classification marking. (b) to obtain information pertaining to the form and nature of the Listing mark or Classification mark to be used for a specific class or category of product. (c) to obtain information or special conditions applying to the product or (d) to obtain the titles and designations of Standards that have been used for investigation of products in a specific category. See Electrical Construction Equipment Directory.