Abstract: An F-shaped panel fastener for securing a panel within a window opening comprises a bracket having first and second parallel flanges extending perpendicularly from a base plate member. The first and second flanges are spaced apart to receive the thickness of the panel edge to be secured between them by a screw inserted through the first flange. Several fasteners are installed around the perimeter of the panel. The panel is installed within an exterior window frame using screws passed through the base plate of each fastener to contact the window frame surface.