100mm/4 inch Gravity Shutter - Black

Ideal fuss free solution when you need to install a hole in an external or internal wall. Suitable for use with 4 inch/100mm fan via round ducting.
- For use with 4 inch/100mm fans
- Compatible with 4 inch/100mm round rigid or flexible ducting
- Prevents backdraught air and rain penetration
- Prevents objects of vermin entering when the ventilation is not in operation