Valve Expert - motul engine LEAD additive - 250ML Additive for gasoline engine requiring the addition of a lead dosage in the fuel All old engines equipped with valve seats not compatible with unleaded gasoline and requiring lead in the gasoline to lubricate and prevent the valves from rising in the seats: Car, Motorcycle, Boat, Motoculture... Not to be used for engines fitted with catalytic converters. Characteristics: Motul engine LEAD additive - 250ML The Phosphorus formulation ensures exceptional lubrication of valve seats and prevents valve lift. Better protection than potassium - based products (Super Blue) and other technologies.