This is the one you remember from when you were a kid. Making engine sounds with baseball cards and clothespins. That idea has been updated with the Speed Blaster Engine Noise Maker. A plastic card from the engine hits the spokes and makes thrilling vroom engine sounds. The Engine is attached to the bike frame with provided zip ties. It is an easy installation and sturdy for the many rides ahead. Also Includes 2 protective knee and elbow pads. A complete set to look your best and be protected. At Zéfal USA we are true cycling fans. We ride...a lot and love the gear to make our rides more fun and safer. Zéfals motto is Keep On Riding and we aim to help you do that!