BDF NA20 Window Film Privacy and Sun Control N20, Black (Dark) - 36in X 12ft DARK, BLACK FINISH that provides excellent daytime privacy, making it hard for unwanted eyes to see through. EXCELLENT HEAT REJECTION. Helps reduce cooling costs especially during the summer through effective blocking of harmful solar rays. NOT RECOMMENDED for DUAL PANE WINDOWS. STRONG ADHESIVES to last many years. For easier installation, remember to use A LOT of soap/water mixture to soak both the adhesive side and window. HIGH QUALITY PERFORMANCE films that are sensitive by nature. Please remember to take caution when handling the film as the slightest fold will create a permanent wrinkle. FREE TOOLS AND EASY INSTALLATION GUIDE to make installation DIY-friendly. Make sure window surface is completely clean and absolutely free of any blemishes.