Mad Cat® Wacky Wool Crinkle Kicker™ are made of natural quality wool that are biodegradable, with no seams, stitching, or stuffing. Roll or toss with the customer combo of catnip and silvervine for the ultimate play experience. These Wacky Wool toys are unique shapes and materials that entince your cat to engage those natural instincts of batting, chasing and pouncing!