A Deadbolt is a lock primarily installed above an exterior lock-set, and functions to provide added security in synchronization with the exterior lock-set. Deadbolts are composed of two key holes on both the interior and exterior, an interior turning knob for easy locking, and a long bolt that protrudes into the door frame when locked. Therefore, deadbolts can tremendously augment the security of the household when coupled with exterior lock-sets.
The advantage of installing a deadbolt is that not only does it cost as little as $25, but it provides a tremendous increase in residential security when coupling with a standard home lock. This minor investment is undoubtedly worth preventing the potential damage and stolen property that can result after a break-in. If you are in the market for higher quality deadbolts, however, they can cost as much as $200.