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 interior and exterior doors to provide security and ease of access. The knob is turned to open the door, while a key or a thumb turn is used to lock or unlock it. These locksets come in various styles and finishes, making them suitable for different types of doors and home decor. Knob locksets are typically easy to install and can be found in residential and commercial settings, offering a practical solution for securing spaces.