I accidentally bought too many on Rakuten, so I'm selling the extras. The following is quoted from the purchase page: ↓↓↓↓↓ Wheel covers to prevent bringing suitcase dirt indoors! Made of stretchy, elastic silicone material. The cover wraps around the wheels to protect the casters. By taking on scratches and dirt, it extends the life of the wheels, allowing you to use your suitcase for longer! In addition to protecting the wheels, it also has a noise reduction effect! By absorbing impacts, it also cuts down on noise that you might be concerned about when moving!