This Defender Security U 11446 Bar Door Lock is a security locking device for hinged swing-in doors, allowing a door to be slightly opened to allow safe viewing and ventilation. This door lock bar can also be installed out of reach of children so they cannot open the door by themselves, providing additional child-safe door security. Adding security bar locks for doors is quick and easy. All installation fasteners, including plastic shim spacers for leveling, are included. Strong, durable, and sure to last, these lock bars are constructed of zinc diecast with a matte black finish. This lock bar is 3-7/8 in. bar length by 2-1/2 in. height and has a long, hinged bar, which folds over the closed door to engage the catch. Please refer to the line art drawing for dimensions and compare with your needs before purchasing.