The sales description shows a high level of "Blackout" ability but that rating is subjective. Having been in the business for several years, if these were produced and sold as such to a customer they would have been going back to the shop with me as unacceptable. "Room Darkening" is a more appropriate description. I have not hung them all but so far, two of the panels differ in length by a distance of greater than 1/2". Also a down side. They're okay otherwise. Time will tell.