A door jamb is a vertical frame that surrounds a door, providing a stable structure for the door to pivot on and a secure anchor for the locking mechanism. It is one of the posts which sit on either side of the door, forming the vertical portions of the door frame. The door jamb bears the weight of the door through its hinges, and most types of door latches and deadbolts extend into a recess in the doorjamb when engaged, making the accuracy of the plumb (i.e. true vertical) and strength of the doorjambs vitally important to the overall operational durability and security of the door. Door jambs can be customized to fit specific door sizes and shapes. The door frame itself is made up of door jambs. The two sides are vertical jambs, while a head jamb can be found at the top of the frame. Combined, these door jambs (along with a mullion) make a door frame.