Our Chew Proof Tread Wheels provide small pets with a fun exercise activity. They are made of powder coated metal and are safe for tails and toes. The Chew Proof Tread Wheels come in an array of colors and are priced to sell. Available in mini, small, medium or large. Fun exercise activity wheel.Safe for tails and toes.Sturdy powder coated metal design.Fun colors.Great value.