Keep your outdoor space-free of nuisance flies with the TERRO® Fly Magnet® disposable fly trap. Eliminating just one female fly can reduce the population by 150 to 500 flies per year. This trap attracts and kills a variety of common flies, including house flies, barn flies, and blowflies, to drastically reduce fly populations around your home. It's also easy to set up - just add water and hang.