These stair treads are medium thickness, soft and fairly stable. They do have rubber type backing that is supposed to keep them in place and for the most part they didn't slip off the stairs when my ten year old was running up and down them. However, I ended up using a non-residue carpet tape that wont hurt hardwood to keep them from scooting around. Every now and then a few of them would be about an inch to the left or right and it drove me crazy, so I decided to secure them better. All in all, these are great and I would recommend them.