Need the quietest Hedgehog wheel on the market? The Silent Runner (12 inch wide) is the one for you! We also offer all metal Treadmill wheels which are constructed of tough heavy-gauge painted (baked-on powder coated) steel. The semi-enclosed design and the solid rear wall also makes Hedgehogs, who are natural “wall-huggers,” feel much safer as they run. Hedgehogs are attracted to the wheel's entry holes — which also offer a really nifty effect when watching them run.