FOOT PETALSWomen's Sock-Free Saviors with Odor Control Insole

what is the fabric on the upper layer?

i have sneakers that my feet slide around in - would these help?

Would these work in peep toe sling back sandals? I have a pair of sandals that are slightly too big. I can’t find heel grippers narrow enough for them

Is the foam quality dense in these? Drug store brands are so thin and flatten irretreavably. These are faily expensive so I was just wondering.