Starbar Fly Trap Attractant lures pesky flies and gnats outdoors with its exclusive, irresistible formula. The 8-pack of odorless, water-soluble pouches contains an effective blend of 9-Tricosene, Indole and Trimethylamine to attract and trap flies and gnats quickly and effectively. Use with Fly Terminator Pro, Captivator Fly Trap, or other water-based traps. Get rid of flies fast!