Larger size for larger vehicles. Treats up to 35 gallons. Fights injector & pump wear. Use regularly when you fill up - treats up to 35 gallons. Formulated to help prevent deposit build-up and corrosion in diesel engines. Without cleaning, deposits can harm performance and waste fuel. STP Diesel Fuel Treatment and Injector Cleaner Helps: Save fuel by keeping injectors clean. Maintain performance by preventing deposit build-up, corrosion and rust. Fight fuel line freeze and wax gel formation. Fight injector and pump wear by improving the lubricity of diesel fuel. Made in the U.S.A.