Bottle Cap Fruit Fly Trap (4-pack) Unlimited Fruit fly protection with these reusable traps. Attaches to any standard soda or water bottle (not included). It's a great way to recycle. Bait used is what you have in your home that the fruit flies are already attracted to. Fruit flies go in and the trap helps prevent them from escaping. Secure attachment helps prevent spills if tipped over. No messy cleanup. Just replace the trap with the original cap and dispose of the bottle properly.