DEF Fluid 55 Gal. Drum/Barrel Price: $275.00 | 275-330 Gal. Tote Price | Free Delivery | API Certified Diesel Exhaust Fluid DEF. Galance Aqueous Urea Solution AUS 32 and API certified Diesel Exhaust Fluid. It is formulated using high purity urea and water. This product is a 32.5% solution designed for use in diesel engines with SCR technology. That is clear, non-toxic and safe to handle.