This was the perfect solution for the standard bed frame we had. We didn’t want to have to use a box spring, but the bed frame had only 4 horizontal supports. Using these vertical slats over the horizontal support was just what we needed and transformed the standard bed frame into a platform bed. We ordered king size, which came in 2 pieces. You will definitely need to screw these slats in place over the horizontal slats, otherwise it will slide. But the wood is very soft so it was easy to do. The wood is definitely super cheap and was splintering significantly. But it got the job done.