A wheel you can use for your robot projects.

It's compatible with Roomba 500-900 tyres (as shown in the picture). It's supposed to be mounted using 3 mm flange (e.g. https://www.amazon.it/dp/B0CKR73ZM9) and, if needed, you can hammer in 3 mm pins on the other side (as in the picture: I'm using a pin that goes into a ball bearing).