'My Bike Sounds Awesome!' Remember putting playing cards in your bike spokes to make cool sound effects? TurboSpoke® Bike Muffler is way better—this sound-amplifying system makes a kid's bicycle look and growl like a dirt bike! Chrome exhaust pipe comes with 3 specially designed, replaceable cards that make different sounds, plus custom decals, clamp and tool kit for easy assembly. Ages 6+.