What is the characteristic feature of a cylindrical lock?

The characteristic feature of a cylindrical lock is that it fits into a pre-drilled opening inside a door. This type of lock is designed to be installed within the body of the door, which allows it to provide a clean, streamlined appearance and enhances the security of the door. The installation process involves creating a round hole in the door, into which the cylindrical lock assembly is inserted, making it less obtrusive compared to other types of locks that may protrude significantly from the surface.

Additionally, while cylindrical locks do typically require a key to engage, that is not what truly distinguishes them; many different lock types also share that feature. Similarly, the confusion surrounding locks used for sliding doors is irrelevant, as cylindrical locks are primarily associated with hinged door applications. The distinction lies in the method of installation and the design of the lock itself.