This chain door lock is constructed of stamped steel and comes in a select plated finish. It features a welded steel chain with all fasteners necessary for complete installation. This chain door lock can be used on a variety of door types. The smaller chain-holder base plate can be mounted on, or beside the door's casing, as it measures only 3/4 in. wide, by 2-3/8 in. tall, and the wider chain lock keeper measures 3-5/16 in. long with a height of 1-3/8 in. This chain door guard also works great as a child-safe security device which can help prevent little ones from fully opening doors and entering or exiting into dangerous and off-limit areas. This security door lock is easy to install and used by many.