Abstract: The purpose of the door lock is to secure a door from both sides temporarily (while building is vacated) with as little damage to door and frame as possible. When the apartment is again occupied, door lock can be used on another residence (apartment). Most rental property has locks on exterior doors that can be operated from the inside without a key. This type of lock is used so that occupants won't have to locate a key in the event of a fire. When the residence is vacated, and the appliances are left, all one needs to do is break a window, enter, open a door, and carry out appliances. The door lock will prevent such burglary by making it virtually impossible to open the door.