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15,886 Flush Bolt Home Design Photos
This is a solid bronze slide bolt with an optional mortise plate for a finished look. Here's the link to the product: http://shop.360yardware.com/Dark-Bronze-Gate-Slide-Bolt-70-300-Gate.htm . In this photo, the slide bolt is oriented vertically to act as security for the courtyard doors.
This surface-mounted security bolt is similar to the cremone bolt, but the rod does not run the length of the door. A flush bolt is the modern equivalent of this, but it is recessed into the door and hidden from view.