*Click "See More" for Measuring Instructions* This product is cordless, child and pet-safe, and certified per WMCA's "Best for Kids Program". The blackout fabric is 100% woven polyester with a 3-pass coated backside which gives 100% blocking of light through the fabric and provides thermal insulation. Attractive-looking fabrics are of the highest quality which gives you custom quality without the custom price. How to choose the right size for mounting inside the window frame: measure horizontally, along the top of your interior window frame. Round down to the nearest. How to choose the right size for mounting outside the window frame: measure horizontally, along the top of your window molding. Round down to the nearest. For optimal coverage, order or more than the width of the window frame. *Please take note that the fabric panel is always smaller than the final blind size that you order. Features Unique spring design with a slow-release mechanism Durable lightweight design and steady premium metal components that mounts both inside and outside the window frame High-quality fabric with an acrylic backing for the best light-blocking and sleek backing appearance Blocks light where room darkening is needed and provides nighttime privacy The cordless operation provides a child-safe and pet-safe environment Adjust the length of your cordless roller shade smoothly and effectively with the slightest pull of the shade. The width of the mounting bracket is 1.7 inches and the height is 1.9 inches The width includes brackets and hardware. The fabric panel will be 1-1/4"" less than the width you order from the drop-down menu.