Lures contain a scent (pheromone) which insects use to communicate. This lure duplicates the scent that scout bees release when they find a good home for their swarm. There is enough scent to last about three months and the special plastic container releases just the right amount. This lure formula is made up of 3 components...proven most effective by USDA research. Lure actually measures 2 3/4" long. Sold individually.