Selling a Carolina Storm Wheel made especially for hedgehogs; may work for other small animals too. 10.5" diameter. Great quality, purchased only a few months ago! I'm just moving across the country at the end of the month and will be buying a new one rather than trying to pack this one. Must be picked up either on Thursday the 21st or Friday the 22nd. $10 OBO, I would be happy to include a litter box that fits underneath it as well.