Locate the difficult to find references and answers quickly. Key Words and Phrases arranged alphabetically with references and page numbers. Greatly increases your speed by getting you familiar with the hard to find code references. Expanded and detailed for easy reading. Simply the best tool available for use with the 2020 National Electrical Code Book. Nothing else on the market is as up to date and complete. I Guarantee it. This Quick Finder Index Contains more than 10,000 key words and includes Electrical Formula pages and Calculation Format insert pages that fit in your code book.