A knob lock is a type of locking mechanism commonly found on doors. It consists of a round knob that can be turned to either lock or unlock the door. When the knob is turned, it engages or disengages a latch, allowing the door to open or close securely. Knob locks are often used in residential settings for interior doors and some exterior doors. These locks typically come in two variations: keyed and keyless. A keyed knob lock requires a physical key to operate, while a keyless knob lock may use a combination or keypad for entry. Both types provide a basic level of security for homes and offices.