PRODUCT DESCRIPTION This Defender Security U 9900 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 chrome finish. This lock bar is 3-7/8 inch bar length by 2-1/2 inch height and has a long, hinged bar, which folds over the closed door to engage the catch. For further dimensional information, please see the line drawing. FROM THE MANUFACTURER This heavy metal constructed door guard comes in a chrome finish. The bar secures your door closed while allowing for 5 In. of viewing or ventilation. Also included are two 1/16 In. door side riser shims to make a perfect fit for your door.