This U 10305 Chain Door Guard Lock is a security locking device for doors, allowing a door to be slightly opened to allow safe viewing and ventilation. This door lock can also be installed out of reach of children so they cannot open the door by themselves, providing additional child-safe door security. Installation is quick and easy with fasteners included, providing added security for your home or office doors. This door guard is constructed of extruded brass with a classic bronze finish and a 6 inch, 8-link welded steel chain. The 3-5/16 inch chain guard can be used on a variety of door types and can be placed over or beside door casing. It features a 6 inch long, 8-link welded steel chain and all installation fasteners necessary for complete install.