When drapes are hung on a window, aside from the beauty they add to a space, they aid in blocking sunlight and the heat/cold that comes through that window. All great details for sure. But what most of them miss is blocking the light that shows at the SIDES of the window which creates a light gap. This is an especially painful thing for drapes with blackout lining that are being used to darken a room. Sure, they block the light completely from coming through the actual drapes but the light peaking around the sides of the window kind of defeats the purpose of the blackout lining to begin with.Because of this, we offer an option to include what are called return sides. This is a technique in drapery making that allows the outer edge of the drapery panel to "return" to the wall and hook into an eyelet (provided) to finish off the drapes at the sides of the window, ensuring better aid in blocking light and of course, creating a more high end look to your drapery panels. This is at no additional cost. If you did see no need for returns, you'll just have an additional 3" of width to your panels and will need one additional ring per panel.