Kaytee Silent Spinner is the wonderful, whisper quiet workout wheel for your furry friend. Patented ball bearing technology makes these wheels super silent while your small pet gets the healthy, stimulating exercise it needs. Provides a quiet workout Promotes healthy exercise Super silent ball bearing technology Each Silent Spinner Wheel features a ribbed running surface that provides traction while remaining safe and comfortable for your furry friends feet. Attach directly to your pets cage, or use the sturdy metal base to stand the wheel on its own! Silent Spinners are ideal for hamsters, mice, and gerbils (Mini and Regular), as well as chinchillas and pet rats (Large). Note: Ships in assorted colors - let us choose one for you! Sizes: Mini: 4.5" Diameter Regular: 6.5" Diameter Large: 10" Diameter Giant: 12" Diameter