Our windows are 29” wide so we had to go with the 27” width so that we could install these inside the frame, which we preferred for a cleaner look and to insulate the room better here in chilly SF. Installation was easy. There is a convenient hidden handle (see pic) to adjust your curtain’s opening/closure. I wish the cost wasn’t so steep (smallest size/27”w is around $100 for just one panel) but hopefully their cost is justified by their durability over time. I am waiting to confirm with Wayfair that it is safe to iron these...