"Secure your home or office doors with additional security with the U 9897 Swing Bar Lock. This door bar lock is a security locking device for hinged, swing-in doors, allowing a door to be slightly opened 2” to allow safe viewing and ventilation. The 3-7/8” long hinged bar folds over the closed door to engage the catch, adding extra security to your swing-in door. 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 swing bar lock is constructed of zinc diecast with a brass finish. It’s strong and durable, sure to last, and installation is quick and easy. All installation fasteners are included, including shim spacers for leveling. 3-7/8” bar length x 2-1/2” height.