This is a piece of heat reflective material which is designed to protect the starter motor of the vehicle from the heat of the exhaust.
The material is aluminiumized reflective material and can withstand up to 2000 degrees F, it is 7″ x 22″ in size.
Often the heat from the exhaust on a track car soaks into the starter motor causing the motor to become lazy and making starting difficult. This product is designed to help prevent this from happening.
Comes as seen in the picture with the clamps to go round the starter and hold the material in place.