What is the Master Key used for? (Granny)

Mastering Lock Picking: 3 Techniques to Open Any LockMr. Locksmith tutorial discusses and demonstrates three lock picking methods: raking, Single Pin Picking (SPP), and a combination of raking and the 'feel' method. The tutorial explains how to get a feel for the pins inside the lock, count them, and calculate their position through slow and deliberate tactile exploration. A slightly advanced technique, involving inserting the pick entirely and slowly withdrawing it to count how many pins fall,