Not super duty as in Ford Super Duty, but as in 300,000 miles of extended coolant protection that protects cooling systems and aluminum components down to minus 26 F. They say Be Coolant features a new-generation earth-friendly biodegradable, propylene-glycol formula. Interestingly, they say it also features a self-sealing capability that is ideal for sealing harline cracks in aluminum engine blocks and cylinder heads.