Silent Spinner, Large Is The Wonderful, Whisper Quiet Workout Wheel For Pet Rats And Chinchillas. Patented Ball Bearing Technology Makes These Wheels Super Silent. Silent Spinners Work Two Ways: Free Standing Or Attach Directly To Any Wire Cage. High Quality Plastic Funning Surface Is Safe And Comfortable For Your Furry Friend'S Feet. Available In Blue, Purple, Red, And Green.