Lucas Safeguard? ethanol fuel conditioner with stabilizers was developed to specifically address issues associated with using ethanol based fuels. This applies to E-10, E-15, E-85, pure ethanol and any mixtures in between including gasoline. Our product is completely soluble in all ethanol fuels and will not harm filters. Lucas Safeguard? ethanol fuel conditioner with stabilizers contains effective additives to prevent rust and corrosion associated with the use of ethanol fuels.