Alfie Pet by Petoga Couture - Jones Exercise Running Wheel for Mouse, Chinchilla, Rat, Gerbil and Dwarf Hamster Measures 4" wide and 1.75" depth. Ideal for hamster, mouse and other small furry animals. This is a fun way to exercise your small animal pets; relieves boredom and increases activity level. They will love it and be entertained for hours. Solid plastic running surface is super safe for pet's feet. Can be easily attached to wire cage Made with pet safe materials. Easy to clean and resistant to odors.