A draught stopper damper is used with inline fans and flexible ducting to stop air flowing in the reverse direction. It has butterfly wings and a very light spring to minimize air leakage within the building envelope.
Made of metal, this draught stopper damper comes in 3 sizes to suit: 100mm, 125mm & 150mm ducting.
Sizing:
100mm diameter | 4 inch
125mm diameter | 5 inch
150mm diameter | 6 inch