Product review (5 stars): After looking EVERYWHERE..these were Perfect!!
My house was just built in 2013 and the builder put in all 3in ducts for the dryer and bathroom vents. so when one needed replacing, I couldn't find them anywhere... Lowes, Ace, and Home Depot only carry 4in. Found these and just put it on today and it was just right!! I bought 5 just in case I need to change my other vents in the future.