These antique brass window stays are designed for timber casement windows. The arms are attached to the window frames and secure the windows open or closed. Open the window by lifting the arm off the sill-mounted pin and then pushing the window out, securing the window open in one of four positions. From Australian company, Tradco Hardware, these antique brass casement stays are also available in a larger size. Install along with an antique brass casement fastener which will secure the window shut.