Keep your outdoor space free of nuisance flies with the TERRO Fly Magnet 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 bottle flies, to drastically reduce fly populations around your home. It's also easy to set up - just add the included bait to the trap, fill with water and hang.