Works Well In Shed
I installed this vent into the roof of a Rubbermaid shed I use to store gasoline and other flammables. It works well to reduce heat buildup during the day. The unit is self contained and weatherproof so I don't have to worry about sparks. It actually runs so fast on a sunny day that it hums. Installation took about an hour, the biggest problem was making a snug 4 1/2 inch round hole that I could caulk to prevent water leakage. I would recommend the square version of this vent if you don't happen to have a hole saw that big but do have a saber saw.

I rated it four stars because it doesn't move as much air as I hoped for, you might want to install two in larger sheds. The unit is well made but I still plan to remove the fan unit in winter. The fan unit locks into the base ring like a smoke dector so I can easily take it off and cover the hole. I have found that items made in warm climates don't usually survive freezing Michigan winters.

Interesting Product
I'm reading some reviews that describe this as nothing more than a toy but it's better than that. Seems to be well made but all plastic and don't know how well it will hold up in the sun over the years. It will move air slowly depending on exposure. It will need direct sun. I've ordred this and one other type of made by a different company that is aluminum. They will be installed in a wall that has some interior dampness due to condensation between the air conditioned space and the exterior wall exposed to direct sun. I don't want a forceful vent and that's exactly what I'll get with this. In the evening or on cloudy days I'll get some passive venting. May need several of these but will start with one or two for now.