Collector Gaskets Solid Aluminum Fits 2-1/2 Inch Diameter 3-Bolt Round Header Collectors Mr GasketMr. Gasket aluminum collector Gaskets are manufactured from dead soft aluminum to easily conform to surface irregularities while providing a tight, leak proof seal. These aluminum collector Gaskets will not shrink, deteriorate, blow out, or burn out. For race, street, towing, or motor homes. Dead soft aluminum conforms to irregular surfaces for better sealing Won't shrink, deteriorate, blow or burn out Ideal for race, street, towing, or motor homes