Hold bottle upright. Unscrew the cap a quarter turn for better venting. Fill the dosing chamber with 25 ml of SONAX Lead Add by squeezing the lower part of the bottle. Unscrew the cap completely and pour the contents into the petrol tank at a ratio of 1:1000 after refuelling. The content of one dosing head (25 ml) is sufficient for 25 litres of unleaded fuel (EN228 norm).