Material SafetyThe Hamster Running Wheel Made of premium PP material, have thick walls and rounded edges. non-toxic and tasteless, can use a long shelf life. it is healthy and harmless to your pets. the diameter of the rollers is 14cm. Anti-slip convex linesThe Pet Hamster roller toy has non-slip convex lines, increase friction and improve stability, avoiding stepsthe errors The cage casters has a diameter of 14cm and is easy to install. It can be easily mounted on the side of the cage or placed inside the cage using the stand. Easy to CleanThe Hamster Exercise Wheel Toy Adopt a transparent and fully open design, it is useful for deep cleaning as there are no corners to hide the droppings. Silent structureThis The Exercise Wheel is designed to be completely silent during hamster play at night. your pet can run at night without disturbing others. Specially designed to spin silently, encourage your pet to get hours of healthy exercise and fun. Wide applicationsThis The racing wheel is designed for hamsters, gerbils, hedgehogs, mice and more similar small animals. It allows these animals to be entertained and exercised, to stay in shape and to stay happy and healthy.