Unit 18: Security & Access Systems 

Chapter 1: Mechanical Locks & Keys — Anatomy Cues Only
Chapter 2: Keycards, Fobs & Biometrics — Status / Readability
Chapter 3: Cameras / Sensors — Lenses, IR Windows, Housings
Chapter 4: Safes & Access Panels — Hinges, Bolts, Seals (No Bypass)