Stp Diesel Fuel Treatment And Injector Cleaner Helps Maintain Engine Performance. Use In Every Tank. Formulated To Help Prevent Deposit Build-Up In Diesel Engines. Without Cleaning, These Deposits Can Harm Performance, Cause Corrosion, And Waste Fuel. Helps Save Fuel By Keeping Injectors Clean. Maintains Performance By Preventing Deposit Build-Up, Corrosion, And Rust. Fights Fuel Line Freeze And Wax Formation.