1.【Safety and environmental protection material】: adopt environmental protection material, safe, no smell, please feel free to use. It's 14.5centimeters in size .Porous design: Increase the ball friction and air circulation, pets will not heat or feel difficult to breathe staying inside for a long time. 2.【Easy to operate】:The both cover is designed with a dark buckle. When the installation is performed, the position of the dark buckle of the cover is aligned with the corresponding position of the running ball, and the cover needs to be screwed until it is screwed to the head.The Lids on both sides cover is the entrance for the pet, and a small hole is reserved in the middle. You can fix the running ball on the bracket and make it into a fixed running wheel. 3.【Exercise toy】: This ball allows the Hamster to mix play and exercise, making it more enjoyable for the hamster and more motivated to keep in good shape. 4.【Funny toy】: Its transparent design will make you see clearly while the hamster doing exercise. Fun exercise toy to maintain your pets alertness and agility. 5.【Interactive toy】: You can put pet into the running ball, let it play freely, and provide interactive fun for pets and pet owners.