Hon&Guan4 Inch Adjustable Air Vent Covers 100mm Ceiling Vent Indoor Vent Covers for Walls Closeable Round Ventilation Cover for Caravans, Cooling and Ventilation Systems

Bought this along with ducting and a new extractor fan. Was simple to fit. Looks well in the ceiling and the opening is adjustable but rotating the centre

Perfect for new ceiling

Easy to fit, just fold the fins in and push it in. If you twist it as you put it in it grips the plasterboard a bit more but might want some dabs of silicone to hold it a bit better.Diffuses the air to help reduce noise and can adjust the opening by twisting the middle circle.I agree with others that it doesn't look pure white. I think because it's not glossy compared to most white surfaces in a bathroom.

Excellent product

Fits perfectly to 100mm vent opening

I got this to make a spray paint booth in my back bedroom.I liked the design and the fact that the inlet area was adjustable on a single screw thread.Its well made, tough and durable.For me it didn't need any fixings as it sort of screws into the opening with the three attached locking vanes expanding out behind it securing the vent to the opening.I am using it for a booth so the wall thickness is about 12mm.I do think it will work well on thicker walls but may need screws or bonding agent like No More Nails etc.For me, it was perfect for the job, looks great and pretty decent price.

Just as described. Quality and appearance good.

this solved the problem