Knightsbridge MLA 100MM/4″ 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”/100mm fan via round ducting. · · · For use with 4”/1mm fans · · Compatible with 4”/1mm round rigid or flexible ducting · · Prevents backdraught air and rain penetration · · Prevents objects of vermin entering when the ventilation is not in operation