Size: 6 inches, enough space for hamster running Eco-friendly and safe material: made of environmental protection resin, transparent, durable and non-toxic br> Easy to clean, the whole ball can be washed with water Encourage healthy exercise in a safe and secure way Makes an excellent training area temporary hold to keep your furry friend on while you clean their homeNot intended for ferrets, guinea pigs and rabbitsHamster Exercise Ball,Hamster Toy for Small Animals 6’’ Running Sport Jogging Wheel,Clear Activity Ball for hamster for mouse rat