100% Polyester For Inside Mount: The shade will be the exact size with no deductions. Measure the width of your window at the top,middle,and bottom. For a 35.5" wide shade, your window should measure between 35.75" to 36.5" wide, for a snug fit with minimal light gaps. Each cordless cell shade comes with a matching PVC head rail and bottom rail Made from a translucent light filtering fabric that is designed to provide privacy while still allowing light to enter the room For inside mount applications please ensure the shade size is at least ¼” smaller than the window recess otherwise it may not fit in your window. For instance, if your window recess width is 35”, you will want to purchase a shade that is 34 ¾” or smaller in width. This product is highly recommended for indoor use only. Questions? Please contact us at the CalyxInteriors website.