This door chain lock is a security locking device for doors. It allows a door to be slightly opened to allow safe viewing and ventilation. It can also be placed out of reach of children, high on a door, so they cannot open the door themselves and enter or exit into dangerous areas. This chain door guard is constructed of extruded brass with a brass finish and a 6-in., 8-link welded steel chain. It is strong and durable, sure to last, and installation is quick and easy. All installation fasteners are included, and it can be used on a variety of door types over or beside door casing. When this chain door guard is fully assembled and engaged, the chain will extend to 4-5/8 in. from base to keeper.