Maurice Franklin Louver-4 Round Brown Polypropylene Plastic Louver with Insect Screen System (Priced Per Bag of 4). Item #4 PLB-100 by Maurice Franklin LouverL8

These are great products from a great company. Here’s the deal on the measurements. If you include the reinforcement ribs on the outside of the diameter, then it is 4 inches. Each rib adds a 1/16 inch to the mounting flange. I put a little construction adhesive on mine just to cover any errors in my drilling. I’m putting around 20 in a 2 car detached garage and I can already tell a big difference with just half of them in so far. Just make sure you use a good quality 4 inch hole saw and face the lovers facing the structure as per instructions.

I like these but gray and black would be nice color additions

Easy to install and a nice fit when I used the DeWalt 4" hole saw ordered at the same time. I put a total of 12 in my soffits. The venting in the soffits seems to have cut down on the drafts inside the house and should make ice dam buildup a thing of the past.

Looks great

However, they are less than 4" diameter. I had to wrap them with electrical tape to get a snug fit in a 4" hole.

Nice covers for venting the soffit of our new addition. I cant ask for more than that. It does what it is supposed to do.