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 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. If you are tired of clipping nails, or are just putting up with the scratches, try a Sandy Trimmer Insert! This exercise wheel contains a soft sand abrasive interior finish. Your pet's nails are trimmed automatically as they run on a Sandy Trimmer Track. Place the wheel in your pets cage for 24-36 hours to automatically trim their nails. This is a glider-safe plastic track, with soft abrasive material permanently bonded to it! The track is washable for easy maintenance. If you already own an Wodent Wheel, we also offer Sandy Trimmer Tracks separately.