Wodent Wheel has an 12 inch diameter, 5.3 inch wide track, and 3.6 inch entry holes. Overall height (on the stand) is 13 inches. Suggested for Hedgehogs, Male rats, Prairie Dogs, and Chinchillas. Color - Black Panels & Green Track. You may also wish to consider the new Silent Runner Wheels which have dual center ball bearings to allow the wheel to spin freely, and do not have the center axle like the Wodent Wheels which can cause injury. Although Wodent wheels have been a standard in the past, the newer Silent Runner Wheels are strongly suggested for their innovative safety and design features. Silent Runner Wheels are safer, smoother running, quieter and allow for direct cage attachment with optional cage attachment hardware ... features not offered with Wodent wheels. We do offer inexpensive Axel Guards and Glider Shields which are safety accessories to cover the center wheel axel. If not properly maintained, Sugar gliders can get their tail fur stuck to the center axel. The Axel guards and Glider Shields can prevent this. Domestic animals are bundles of energy. As such, they need suitable, safe, and secure ways to release all their pent up energy while also getting beneficial exercise to keep them healthy. The Wodent Wheel safely satisfies these pet needs. This wheel won't catch or pinch your pet's tiny feet and tail the way traditional wire exercise wheels can. Rugged wheel base construction and weighted design won't tip over under normal use.