The Polini Big Evolution diaphragm is made from the words: "More air, more fuel, more performance!". The 0.3mm thick carbon diaphragm blades are tightly sealed against a very good vulcanization, which is made to withstand gasoline and not least the high operating temperature. The mounting plate is CNC-milled and then anodized. Note: The engine block must be milled to accommodate this diaphragm.