Heavy Duty Silicone Heater Hose 2 Ply Blue Silicone Hose. High Durability Construction: Polyester-reinforced silicone ensures extreme durability for high-temperature use. SAE J20R3 Class A Compliance: Exceeds SAE 20R3 Class A performance standards for automotive coolant systems. Superior Environmental Resistance: Resistant to weathering, coolant deterioration, and ozone exposure. High Flexibility: Designed for versatile applications in radiators and heater systems. OEM and ODM Services: Full customization, minor customization, and design-based options available. Comprehensive Quality Inspection: 100% visual and function inspection for all finished products. ISO14001 Certified Manufacturer: Operates with certified management systems and traceable raw materials.