A professional Petrol additive developed to lubricate and protect soft valve seats from wear, allowing the vehicle to run safely on modern, unleaded petrol. This additive is recommended for classic and vintage cars still on the road which are running on unleaded petrol whilst having been designed to run on leaded fuel. This additive has been designed as a replacement for lead in petrol because of the arbitrary market requirement for environmentally friendly fuel formulations. Fuel can no longer contain lead (Tetra Ethyl Lead) in the 21st century. The biggest issue for old cars using unleaded fuel is valve seat recession since the lead in the fuel formed a protective coating on the exhaust valve. Suitable for all two and four-stroke petrol engines turbocharged and non-turbocharged. Add 25 ml per 25 litres of unleaded petrol fuel (1:1000) each time before filling up.