Review on 🌀 Uxcell Plastic Single Rolling 8mmx25mm - Efficient and Durable Roller for Your Projects by Ben Boulanger

Blue hard plastic part. While the black part isn't rubber, it doesn't feel like plastic either. It is rather the soft part of the sneaker that is underneath the typical black sole of the sneaker. I threw them in the bin in January 2019 as a replacement for a worn out plastic tire. So far, so good.