Made from durable, non-toxic materials, our felt pads are an easy way to add an extra level of elegance to your Cat Exercise Wheel. Unlike the traction pads that line the interior running surface of the wheel, these outer pads are specifically sized to fit the spaces along the exterior faces of your Cat Exercise Wheel's center tracks. One set of outer wheel pads will cover the exterior of one Gen 7 wheel.  Please note that these pads are for exterior use only and will not work as interior traction pads. Compatible with Gen 7 Cat Exercise Wheels only.