This swing bar door lock is constructed from heavy-duty diecast zinc and comes plated in a satin nickel finish. The 3-7/8 in. long hinged bar folds over the closed door to engage the catch adding extra security to your swing-in door while allowing up to 2 in. of safe viewing space or secure ventilation. This door lock includes all necessary fasteners including plastic shim spacers (for leveling, if required under mounting plates) for a quick and easy installation.