PreVent-It Soffit Vents 4 Inch - Only Design that Prevents Moist Air from Re-entering Home, Under Eave Exterior Vents for Bathroom Exhaust Fan, Screws Included, White, 4-Pack

Wanted to get an exhaust vent where I didn't have to drill through the roof and introduce a potential leak. This fit the bill and directs the humid air away from the house preventing any moisture buildup on the soffit. Time will tell how it holds up, but so far it works great and love that I didn't have to drill thru the roof

NOT RECOMMENDED FOR ANY CFM > 50.For high CFM, If you bought a 1.0 or less sone fan, expect it to jump to 2-3 sones. And likely rattle.You are better off getting something from the Lowe’s shelf that outlets air STRAIGHT DOWN.Design/Build quality is not great for high CFM case, but should be ok with low air pressure. It's easier to turn a car going 20 than 60.I can see they tried to make the design low profile, it looks nice. However, the sharp 90 has a serious airflow restriction where the total area is reduced to a quarter of the 4inch tube diameter.If you want to know what that sounds like, plug your fan in and put your hand over the exhaust. Your fan is going to work extra hard and will lose performance TREMENDOUSLY.I installed this exhaust vent at the end of 10ft and 20ft rigid pipes (straight to the soffit.) If you are the seller reading this, take note, the sheer amount of momentum created down a 10-20ft pipe will be like the fan's energy hitting a brick wall when it reaches your outlet. The elastic compression of the air will bounce back up the pipe and you will get a rattling sound from quick drops in pressure at the backflow flap.I didn't realize how narrow the device was until I purchased it. I would double/triple the depth of turn to keep the device compatible with 80-110CFM fans. If the seller wanted to keep the design but reduce the impact return, at least make the inlet at a straight 45DEG.imo, the seller should mark the product for 50CFM or less (not 110.) Or delist it. I will rip and replace all my units.Seller's QA should practice installing test designs with rigid piping of at least 5ft in between outlet and fan. (This is a worst case scenario with momentum at endpoint.)

I upgraded all my bathroom fans and this design for the exhaust vents worked just right. It was easy to hook up and it did not take a genius to make it look like a professional job for a do-it-yourselfer.

When he says, Yeah, these are great, I believe him. Easy to install. I think it took him all of about 30 minutes to remove the old vents, clean out the ductwork, reattach (or I should say attach as the ductwork as never attached to the old vents), and put up these vents.