4 Inch Backdraft Damper Duct 2 Pack One Way Airflow Insert For Ducting In Range Hoods Bathrooms Fans And Kitchen Fans Heavy Duty Galvanized Steel With Stainless Steel Axis And Spring Easy Install

4 Inch Backdraft Damper Duct Set, 2 Pack in Galvanized Steel
✔️ 100 mm (4 in) dia, 88 mm (3.5 in) length, 0.5 mm thick, 2-pack

The 4 inch backdraft damper is a heavy-duty duct insert designed to stop backflow in exhaust lines, range hoods, bathrooms, and other ventilation runs. It uses a galvanized steel shell with a stainless steel axis and spring for durability and reliable operation.

✅ Diameter 100 mm (4 in), length 88 mm (3.5 in), thickness 0.5 mm (0.02 in)
✅ Body: galvanized steel; axis and spring: stainless steel
✅ Pack of 2 units for multiple ducts
✅ Easy installation: insert into duct until it stops; ensure spring is horizontal for proper operation
✅ One-way airflow design: dampers open only toward exhaust direction

💡 What is a backdraft damper for ducts and how does it help ventilation?

This handy device keeps air moving in one direction and stops backflow that can bring fumes into living spaces.

• prevents backflow of stale air and odors in ductwork
• improves indoor air quality in homes and workshops
• works with standard round ducts like 100 mm / 4 inch
• durable galvanized shell with stainless steel spring for longevity