Thank you for viewing. This is a running wheel for small animals. It's a Harmony Wheel, 17cm. This is a set of two of the same product. These are 17cm wheels that came with a GEX cage. They weren't the right size for my pet, so I didn't use them (I did let them run on it a little to test). So, what I'm selling this time is the 17cm wheel and a slightly larger base for a 21cm wheel. They can be used without any problems. There are no noticeable scratches or stains, and they are in beautiful condition, almost new. Please note that the box is not included. I will pack them securely. If you have any questions, please feel free to contact me.