These wheels are perfect for what we need! We attached them to the bottom of our rabbit's cage to make it easier to move him from place to place. We no longer have to pick it up or scratch it around the room. Now he and his cage slide easily. These instant wheels easily stick to the plastic. We followed the instructions and sanded down 4 rough spots on the plastic. Then we attach the wheels. They have been in the cage for over a month and are doing well.