Aspen 4 is virtually free from harmful substances such as benzene, aromatic hydrocarbons or olefins; substances that can cause serious health problems. Aspen Alkylate Petrol also keeps the spark plugs and combustion chamber of your machine cleaner. Aspen can be stored for a long time without any deterioration in quality, which makes your engine easy to start – even after long standstill periods. There are numerous environmental benefits, such as reducing the formation of ground-level ozone (smog) by about 40%.