This trap uses a food-based lure and color proven attractive to fruit flies. Simply add the liquid attractant to the trap and it starts catching fruit flies within minutes. Each trap comes with a 30-day supply of attractant and is reusable with RESCUE! Fruit Fly Trap Attractant Refills. With more holes and a higher concentration of attractant, our exclusive design is proven to catch adult fruit flies eight times better than competitive traps.