A flange gasket, also known as a seal or spacer, is a component used to create a tight seal between two surfaces in exhaust system. The flange gasket is made of high-quality materials such as rubber or metal and is designed to withstand high temperatures and pressure. It is placed between the exhaust manifold and the exhaust pipe to prevent exhaust gases from leaking out of the joint and causing damage to other components. The flange gasket ensures that the exhaust system operates efficiently by preventing any unwanted air leaks.