Important Inside Mount Measuring Instructions: This cellular shade is the exact size - no deductions are made. Measure the width across the top, middle, and bottom of window. Ensure your window measures 38.25" to 39" wide for a 38" wide cellular shade. This allows proper fit with minimal light gaps. Measure the height from the top of the window to the windowsill on the left, middle, and right of the window. The largest measurement will be the height you order. EASY, STRESS-FREE INSTALLATION - Our window treatments come with all of the necessary mounting hardware and simple instructions for quick, easy installation. Their sturdy construction and easy use ensure that these shades will be a durable, long-lasting upgrade to any space. Each cordless cellular shades blinds comes with a matching pvc headrail and bottom rail. Inside mount, ceiling mount, or outside mount hardware included in shipment. Room darkening blackout shades offer excellent insulation problems and the block out the light. Please ask us any questions you may have prior to making your purchase to ensure your window treatment is the right fit and style. If you are not absolutely certain, we recommend ordering one blind as a trial to minimize a potential return expense. Our 9/16" Single Cell Blackout Cordless Cellular Shades blinds are the perfect choice if safety or ease of use are a primary concern. Because there are no cords on these shades, they are an excellent choice if you have children in the home. Moreover, they offer excellent insulation problems and the block out the light. These are a wonderful choice for a bedroom, bathroom, TV room or anywhere where you want to blockout the light, which of course saves on summer heating bills. This shade is a great insulator in the winter too, as its honeycombs trap cold air.