These classifications help identify the appropriate type of backset for different doors. For example, a typical lock specification might look like this: https://locksmithcal.com/locksmith-in-victorville-ca/

DIN 18 251-1, PZ (Profile Cylinder), Class 2 (locks for interior doors with higher requirements), 65 mm (backset), 72 mm (distance from the center of the keyhole to the handle), and 20 mm (faceplate width).

Understanding the backset and its classifications is crucial for choosing the right lock for your door, ensuring both safety and proper function.