Environmental friendly material: Hamster exercise wheels are made by high quality environmental friendly plastic materials to protect pet health. This product uses a new PC material with a lock. It is easy, convenient and quick to install this product Hollow wheel: The design of making both sides of the running wheel hollow allows hamsters to breathe easily and do aerobic sports. There are several reliable air holes in the wheel, your pet can have fun in the wheel for a long time Transparent Wheel: Pets can have fun in the wide and wide hamster running wheel. transparent and you can observe your pet's every movement, it's interesting Simple installation: With the lock, you just need to press it lightly to assemble this product, it's easy to install DIY Combination Toys: This small hamster wheel can be connected with the other tubes, allowing you to create the other combinations to increase the difficulty of the game for your pet