2020 Master Exam Preparation Book Package Paperback With Answer Key Code sticker This is a great self-study book program that provides in-depth instruction on Theory, Code, and Calculations.This library includes:Electrical Exam Preparation TextbookUnderstanding the NEC, Volume 1, Articles 90-480 TextbookUnderstanding the NEC, Volume 2, Articles 500-820 TextbookElectrical Theory TextbookMaster/Contractor Practice ExamDigital Answer Key(s) included with this product.