This was purchased to replace an old, and in windy conditions very noisy, plastic vent. Installation was a simple matter; and whilst the non-return flap in the new vent does make a noise when it's windy (reflected in the four-star rating: if I could do so I'd give it four-and-a half) it's a lot quieter than the old one. The vent looks very smart and being stainless steel this won't suffer UV degradation as did the plastic one 9and should be easy to clean when the time comes). Overall, pleased with the product and very pleased with the service from i-sells.