These foam pieces are perfect to put up against the wall to block the gap between my matress and the wall. They fit from head rail to foot rail on a standard crib, it comes with 2 separate foam pieces that go under the fitted sheet.

They are so portable. Much better than dealing with a railing. Actually using in an rv bunk to keep from rolling out.

They stay securely under the fitted sheet of my queen size bed. I will feel safe using them when my granddaughter spends the night. They fit fine under the pad and the fitted sheets. They don't deflate and have not shrunk.

If you intentionally avoid fire-retardants, you should be concerned. These chemicals are structurally similar to dehp - a chemical banned for use in children's products.