Aspen is made from alkylate petrol which is made from the gases from the top of the distillation tower which are synthetically modified into a liquid again.
The result is;
a petrol that is virtually free from sulphur, benzene and aromatics (solvents)
is ethanol free is chemically inert - can leave the fuel in machinery and will start easily next time
a low odour - you are breathing much cleaner air when working with your power tools
Use Aspen 4 and you will discover a much cleaner and more environmentally way to cut your lawn without the need to change your petrol mower.