Zerex Heavy Duty Extended Life Antifreeze/Coolant, Ready to Use - 1gal (Case of 6) (ZXEDRU1-6PK) Fully formulated or pre-charged to protect against liner pitting and hard water scale 3 Years/300,000 mile protection guaranteed Meets the Caterpillar EC-1, Cummins 14603, and DDC long-life specifications Extend drain interval to 6 years, 14,000 hours, or 600,000 miles with the use of Zerex Extended Life Extender