Code Check's newest and most comprehensive book is based on the 2021 IRC, UPC, UMC, and other current codes, including the 2020 NEC. It has 330 pages, including 336 illustrations and 192 tables. It includes material not found in any of our previous individual books. The book is designed for inspectors, plans examiners, contractors, home inspectors, do-it-yourselfers, and educators. The book includes notations and explanations of major changes from the previous editions of the codes, so it can be used in areas using either the 2018 or the 2021 model codes. These are the most widely used codes in the United States.