The MouseBro Windmill Silent Candy-Color Hamster Wheel with Height-Adjustable Base and Cage Attachment for Hamsters, Gerbils, Dwarf Hamsters, Mice, Rat, and Other Small Animals is an adjustable height design that makes it possible for every small animal to start their happy running easily. The windmill outlook is super cute and creates a fun fairy tale world for your pet. The wheel features four slits for enhanced ventilation, which means when your pet runs and exercises, a steady stream of wind helps them cool off. The raised grooves ensure friction when pets are running, so they have no difficulty getting the wheel to spin. The MouseBro Windmill Silent Candy-Color Hamster Wheel with Height-Adjustable Base and Cage Attachment for Hamsters, Gerbils, Dwarf Hamsters, Mice, Rat, and Other Small Animals is made of polypropylene for durability and long lasting use.