The Builder’s Best 4″ x 50′ Foil Duct is a high-quality, professional-grade solution designed for use in HVAC systems operating under low to medium pressure conditions. Constructed with a multi-ply aluminum/polyester laminate and metalized polyester, this duct delivers strength, flexibility, and long-lasting durability. Its design includes a steel wire helix that provides sturdy support and ensures the duct holds its shape during installation and use. The encapsulated wire construction also prevents unraveling when the duct is cut to length, making it easier and safer to work with.

This foil duct features an airtight construction and a smooth inner core, promoting efficient airflow and reducing air resistance within the system. It meets strict safety and performance standards with a UL 181 Class 1 Air Connector label and includes a UL sticker every 10 feet for easy verification. Additionally, the duct meets NFPA 90A and 90B requirements, making it a dependable choice for a wide range of HVAC applications.

Designed for tear and puncture resistance, the Builders Best foil duct withstands job site handling and maintains its integrity over time. Its PRO performance level makes it suitable for both residential and commercial installations. Please note: this product is not intended for venting appliances used for cooking, heating, or clothes drying unless specifically approved and recommended by the appliance manufacturer. For HVAC applications demanding durability and reliable performance, this 4″ x 50′ foil duct is a trusted and efficient solution.

• Multi-ply foil design with aluminum/polyester laminate and metalized polyester offers strength, flexibility, and long-lasting performance in HVAC systems
• WBuilt with a steel wire helix that maintains shape, prevents unraveling when cut, and ensures easy, stable installation in low to medium pressure systems
• Smooth inner core promotes efficient, unrestricted airflow while the airtight construction helps maintain system performance and energy efficiency
• UL 181 Class 1 Air Connector label with a UL sticker every 10 feet; meets NFPA 90A and 90B for reliable use in both residential and commercial HVAC setups
• Tough, puncture- and tear-resistant foil ducting stands up to rough handling on job sites for dependable, professional-grade results
• Color: silver
• Dimensions (L x W x H): 18.75 x 11.00 x 5.25 inches
• Weight: 4.18 pounds
• Manufacturer warranty: 30-Day Warranty