A pin tumbler lock is a common type of lock used in doors and padlocks. It operates using a series of small pins that are arranged in pairs, with each pair consisting of a top pin and a bottom pin. When the correct key is inserted, it pushes the pins to the right height, allowing the lock to turn and open. These locks are widely used because they are relatively simple to manufacture and can be easily rekeyed. The design provides a good level of security, making them popular in residential and commercial settings, as well as in various types of safes and cabinets.