This chain door guard is constructed of a steel chain, diecast housing, plate and keeper, and it comes in brass-plated finish. This lock engages by allowing the bolt to slide into the keyed mechanism to lock, and it uses a B1 keyway, ILCO (1098M). This chain door lock allows a door to open slightly for safe viewing and ventilation. Installation of this lock placed out of children’s reach will help prevent them from opening a door themselves to enter or exit into dangerous areas. All installation fasteners are included, and it can be used on a variety of door types, on or beside the door casing.