A type of lockset comprising two knobs connected to a retractor case inclusive with a special type of latch with anti thrust plunger. They are available with a variety of locking functions incorporating keys and turns for use on entrance doors, passage doors, privacy doors etc. Considered simple to fit however preparation requires a fairly large hole through the face of the door to house the mechanism. Difficult to return back to normal locks/latches once a door has been cut for a knobset limiting the choice available for handle styles. The images below show an entrance knobset (has a key facility) and a passage knobset.