Diesel Particulate Filters are becoming standard fitment on almost all late diesel vehicles. A Diesel Particulate Filter or DPF as they are known is just that a "filter" or "soot trap", its function is to trap the harmful soot particles found in diesel exhaust gas emmisions. DPF's need to be cleaned through a process called regeneration but due to such things as driving habits,use of Biodiesel fuel and the wrong type or grade of engine oil (many modern diesel engines require a LOW ASH oil), DPF's can become blocked.JLM Diesel Particulate Filter Cleaner can help with the regeneration process.This 100ml bottle can treat up to 60 litres of fuel and comes with its own pouring funnel(not shown).