This a great joke gadget that you fit inside someones exhaust pipe on their car, motorbike or van. To fit it in place you just spread the flanges until it fits snugly in the exhaust pipe. Your victim won't know what you have done to their car. When they drive the car they will hear a loud whistling sound following them wherever they drive. They won't know why their car is making the noise!
The exhaust whistle can be removed from the exhaust pipe and reused time and time again so you can get friends, family and workmates with the same joke over and over again. They make great gifts and come with instructions.