Product review (4 stars): Does Work, But CAUTION, It Does Snag Lint
I'm giving this a four because although it works, the lint from the dryer clogs it within a week and we have just two people in our household.  It was really easy to put in, I did it w/o the husband's help. Simply and gentle bend out the flaps on your dryer vent grids. I have new construction and they popped out really easy. Slip this over the hole and put the vents back on. I have to go out and clean it every week. I live in Northern WI, I'm not looking forward to cleaning it in the cold. But it does beat having mice in my house or birds nesting.