12-Concepts Simplified 12-Concepts: Intro 1 12-Concepts: Intro 2 12-Concepts: C1 12-Concepts: C2 12-Concepts: C3 12-Concepts: General Service Structure 12-Concepts: C4 12-Concepts: C5 12-Concepts: C6 12-Concepts: C7 12-Concepts: C8 12-Concepts: C9 12-Concepts: C10 12-Concepts: C11 12-Concepts: C12 12-Concepts: Warranty 1 12-Concepts: Warranty 2 12-Concepts: Warranty 3 12-Concepts: Warranty 4 12-Concepts: Warranty 5 12-Concepts: Warranty 6