I have a large backyard with somewhat swampy woods behind it about 1/5 of a acre.  With all the rain in our area I literally had swarms of mosquitos and could not enjoy the deck or the yard.  I decided to try this and gave it 24 hours.  What a difference!  I am writing this from my deck, have been out here reading for 2 hours and not one bite!!  This product is great and is performing even better than I thought.  I am one of those people that mosquitoes love to feast on and I really don't like spraying chemicals on my skin.  I figure it is covering both me and my neighbors yards as it is rated for 1 acre.