For ethanol fuels. Removes ethanol fuel deposits. Treats up to 21 gallons. Saves gas. For E10, E15 & E85 fuels. Gas with 10% ethanol is E10; gas with 15% ethanol is E15; gas with 85% ethanol is E85. 1 bottle = 1 use. Like conventional gas, ethanol fuels leave deposits that harm engine performance. Use every oil change or 4,000 miles. STP Fuel System Cleaner for Ethanol Helps: fight fuel economy loss due to ethanol fuel deposits; prevent rust & corrosion; save gas and lower emissions by removing fuel system deposits. 100% satisfaction guaranteed. STP does not manufacture any private label products. www.stp.com. Made in the USA.