Keep fly populations under control! The RESCUE!® Disposable Fly Traps bait is irresistible to flies. This attractant is comprised of food and feed ingredients, and other food flavorings generally recognized as safe. The attractant dissolves and activates when water is added to the bag. Lured by the scent, flies enter the trap through the yellow top cap and drown in the water. This fly trap is great for barns, garages, and homes. Disposable Fly Trap catches hundreds of the most prevalent species including house flies, false stable flies, blow flies, blue and green bottle flies, flesh flies, face flies and many others.