Pertronix D172400 Flame-Thrower Plug and Play Vacuum Advance Electronic Distributor with Ignitor for British 25D 4-Cylinder Engine All new lightweight cast aluminum housings Tailored advance curve for optimal performance and drivability Integrated Ignitor electronic ignition delivers twice the voltage to the spark plugs, increasing horsepower, fuel economy, and spark plug life Rotating cobalt magnets trigger a Hall Effect integrated circuit which enables precise timing High dielectric strength cap with brass terminals