We have tried a variety of flytraps to keep our fly situation under control. Between our dogs and our chickens, we are overrun in the summer without some sort of countermeasures. These traps are by far the most effective format we've tried. They work best if they're about an inch off the ground, and if they're arranged over something the flies are already attracted to.. (Fresh poops work the best.) I move mine around every day or two, and I will fill them completely up several times a summer. If not overfilled, they don't spill when tipped, and they actually can be reused if you just shake them to extract the dead fly juice (smelly operation though). On the whole, highly recommend!