A knob lockset is a type of door hardware that combines a doorknob and a locking mechanism in one unit. It is commonly used on residential doors, providing both functionality and security. The knob allows users to easily open and close the door, while the lock ensures that the door can be secured when needed. Typically, knob locksets are installed on interior and exterior doors. They come in various styles and finishes to match different home decors. Some knob locksets also feature a keyhole for added security, allowing users to lock and unlock the door with a key, enhancing safety for homes and businesses.