This bait works!! It smells horrible (like decaying carcass) and the flies die to get in. It fills up rather quickly, and it gags me to empty it! You have to hold your breath, but this system is convenient and helps a lot in reducing the pesky fly population. I learned the hard way a few years ago not to use a fly swatter outside....the more you swat them, the more they come in droves as they are attracted to any blood residue. This helps to divert them away.