Product review (5 stars): Simple solution but check how high up your vent is!
Stopped water leakage on inside of wall when the winds grew fierce and drove water right into old vent and dripping down the inside wall. Thought I needed a new window. Only needed a new vent cover!
Good product but my vent is installed SO HIGH over my sliding glass door, it requires a step stool to reach it, so it is actually a two-part solution and it fills up fast.