The bevy of different lock cylinders can be confusing, but remember that the components don't determine whether it is a pin tumbler or wafer cylinder. The difference is in how they are assembled. Pin tumblers and wafer cylinders use similar parts. A "cylinder" consists of both the lock body, the metal shell that holds components inside the door and attaches to the doorjamb with screws or adhesive, and interior working components (i.e., springs, pins, driver pins). Do not confuse this with a deadbolt cylinder/housing unit, which consists only of the housing attached to the door and not to the jamb by screws or adhesive, most doors have a deadbolt cylinder already installed within the body of the door. To understand pin tumbler and wafer locking mechanisms, it is helpful to understand how they work from the inside out. There are three main components in all locks, cylindrical lock body, plug, and driver pins. Pin tumbler cylinders have a keyway and are often pin tumblers.