You don't the permission to view this video
There are two types of deadbolts: single cylinder and double cylinder. A single cylinder deadbolt must be opened with a key from the outside and a turn on the inside. If your door has a sidelight or a glass pane, I suggest a double cylinder deadbolt. With this type, an intruder can’t break the glass and reach in and unlock the bolt. This design does present a danger, however, in case of a fire, as a key has to be used to exit.