Environmental Protection Material: Safe, No Smell, We have improved the material of the product, even if the Exercise ball collides, it will not break, Sturdy and durable. Product Feature: Snap-on design, through the air outlet, Increase the ball friction and air circulation, pets will not heat or feel difficult to breathe staying inside for a long time. Its transparent design will make you see clearly whilethe hamster doing exercise. and you can play together with your pet to increase more pleasure. Keep Healthy & Breathable Running Ball: There are multiple vent holes on the ball, which is safe and breathable, and your small pets can play in it! Holes design on both sides of the running wheel which make it more breathable and allow hamsters to aerobic exercise. Transparent & Fashionable Ball: Its transparent design will make you see clearly while the hamster doing exercise, and you can play together with your pet to increase more pleasure. Easy to Install: 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 runningwheel. DIY a Special Toy for Your Pets: This small hamster ball can be connected to external hamster tubes, and with unlimited extension, which allowing you to DIY combinations to increase the difficulty of exercise for pets!