We put the classic Master Lock 5400 series combo box under the microscope and decoded it step-by-step. No force, no destruction—just technique. This video breaks down how the internal wheels behave, what to feel for, and how a simple decoding method can bypass most common combination lock boxes. If you’re learning lockpicking, physical security, or just want to understand how these mechanisms really work, this one’s for you. ⚠️ For educational and security testing only. Always practice on locks

How to Set or Reset Combination: Master Lock 5400D Key Box