I purchased these holders to store my children's toothbrushes up, out of the way. They fit the Kids' Sonicare toothbrushes great.I mounted them on a tile wall without any trouble. I made sure the area was clean and dry. To mount, pressed and held the holder for about 30 seconds after sticking it to the wall. I also waited overnight before putting the toothbrushes in the holders to make sure the mounting was solid. So far, I haven't had any issues with them coming off the wall. If I do need to move or re-mount, I'll use the red/black Scotch Mounting Tape (that stuff seems to work on everything).I also like that I can pull the grey liner out of the holders (without removing them from the wall) to wash. That will keep things nice and clean. I'm very happy with this purchase.