4 Inch Round Air Vent, HG Power Adjustable ABS Vent Cover, White Louver Grille Vent Fit for Bathroom, Office, Kitchen, Ventilation Use - Opening Size 3.74"

Inexpensive. I needed a "vent" for a 4" duct in my basement that was wide open. This fit snug into the galvanized T- fitting and I was able to adjust/close the open 'port'. Works perfectly. Sure metal would have been nice, but they are also a lot more expensive, and the white would match a dropped ceiling if I installed one.

Muy bueno y bonito,espectacular,me encanto

Looks good against the white ceiling tile and easy to use and attach to tile. Lost the star because it's light plastic. East to open/close and the air feels like it flows evenly out.

Product received

Does not have anything to hold the vent into the duct, much duct tape had to be used to keep it from falling out.

I don't do many reviews. Great design, easy install & regulation on incoming air. Fit secure

Perfect size and look for what we were going for in our new office spaces. Easy to install.

Bought these for my 200 sqft cabin to add fresh air in. It's spray foamed, so I ddin't want to suffocate in the winter! I had been leery of adding vents due to extra heat loss, but these are just the ticket!They have a knob on the fron that you twist to open or close, and it's a little or a lot! You do have to add another end to it for the outside, and maybe a chunk of PVC tubing depending on your walls.It even has little "holding fins" on the sides to hold it in place in your hole, so be sure to twist them in the right direction when inserting.Only downside is they will be tricky to install with walls of a differing thickness (mine are 1" thick).Seem well made, nice quality plastic, an worth the money for sure. If you don't like the color, just lightly spray paint them ;)**Edited to add**I JUST installed these. not sure if I can post a link, but here is an amazon product that I bought to use on the outer wall with these: https://www.amazon.com/Deflecto-Dryer-Mouth-White-RVHAW4/dp/B00DM8L178/ref=psdc_13397451_t2_B073HH3ZGMI'm going to pull off the metal tube, I already sued a chunk of pvc inside the walls which I found in the plumbing section of my hardware store . . . fits inside this nicely and gives me JUST enough extensionthrough a 4" wall. A bit of clear silicone to attach the two and viola, there it is. looking forward to seeing how well they circulate air! If you use for a single room structure (cabin/shed) make sure to study airflow charts on various designs on curculation. I put one of mine 12" from the floor and the other aross the room in the loft wall, so air will flow down and up one sde to the other :)