Tradco Narrow Sash Fastener Sash Fasteners are commonly used where ventilation is desired, e.g. kitchen or a bathroom, to ensure closed windows stay secure. Sash Fastener Function - are usually fastened closed or semi-open to a mortice plate or hook plate screwed to the window frame and are screwed to the edge of the window. Specifications: Length: 69mm Width: 17mm Base Size: 15mm Catch Size: 11mm Available Finish: Antique Brass Antique Copper Chrome Plated Matt Black Polished Brass Polished Nickel Rumbled Nickel Satin Brass Satin Chrome Satin Nickel