Unlike a most spring-bolt locks, in which the bolt is held in place only by the pressure of a spring and can easily be retracted, a deadbolt lock cannot be opened except by rotating the lock cylinder.
A variant of the standard deadbolt is the vertical deadbolt, which generally rests on top of a door. Vertical deadbolts resist jimmying (in which an intruder inserts a pry bar between the door and the frame and tries to pry the bolt out of the jamb).
 Common Types
Single Cylinder
Double Cylinder
Single Cylinder with removable thumbturn
Security Features
Many designs are available from manufacturers. Various manufacturers have patented designs offering unique solutions to prevent the locks from being defeated by picking, lock bumping prying, and other forceful attacks |
