Silverhook Longlife Antifreeze & Summer Coolant is ethylene glycol based and is formulated with advanced OAT (Organic Acid Technology) to offer up to 5 years protection. Use in your cooling system for all year round protection against winter freezing, summer overheating and corrosion. Silverhook antifreeze is suitable for all types of engines including aluminium. (-25 Celsius at 50% dilution)