I was happy to receive but discovered that I had chosen a vertical instead of horizontal that I needed. I made it work. Left the original boards underneath and laid this on top. There are 2 for the standard king sized.  They did give me the support I was looking for; however only 4* because they slide all over.  One morni g I woke up and about slid out of the bed. The mattress was shifted about 1/3 off the bed. Never had that issue before so tried putting a cotton sheet on the boards thinking they would stay put. They did not.  They slide and bunch of toward the middle. Hassle as I have been recuperating from surgery.