dimensions can be found at HVACquick.com I cut off the electric box on the side and the mount so it would fit through my 6 inch vent hole. I have mine hanging out the back into the attic. I'm fortunate enough to have my cabinet against a wall that allows me to vent to the attic. With all that stuff cut off it is about 5 1/2 inches diameter and about 9inches long(guessing). You could probably cut off 2 inches from the length if you are handy with a saw. If you got this I would put it outside the grow box, but it can also fit inside I'm sure. I just got fed up with the computer fan thing early on as they did not move even enough air for my seedling lights. So I started in with the small inline duct fans. The MIXVENT was my third and final try. Hope you don't waste as much money as I did. They say to go big as you can always dial a fan down, but I did not listen. Please post what you decided and how it worked out.