Mag 1, Gallon, 5W40 Full Synthetic Diesel Oil, Wear Protection Significantly Exceeding API CJ-4 & The Toughest Orem Specifications, High Detergency, Superior Dispersancy Keep Engines & Pistons Clean & Soot Suspended, Despite Longer Drain Intervals & Increased Soot Loading, Higher Starting TBN 10.0 Provides Added Oxidation Control & Protection Against Acid Build-Up That Can Cause Rust & Corrosion, Excellent TBN Retention, Excellent Oxidation Control & Piston Cleanliness.