The product came 'agressively packaged' and I was worried there may be some damage, but the beauty of this material is that it immediately bounced back to its former shape once freed from the packaging.
I slipped them under the sheets while still in the plastic to see if they would really work as claimed (I was still unconvinved at this point) and they kept slipping off the bed. Before I gave up I decided to take one out of the packaging and, of course, it worked brilliantly - the material means it holds in place wonderfully.
Though my one year old can deliberately climb out, he cannot accidentally fall out.
Recommended.