I have been using the Fly bags for 2 years now and will continue. Here in NC where I live we have a LOT of Chicken Houses and the black flies are bad. Hanging the bags around 30 feet from the house stop them from coming inside.
The trap works really great had the trap hanging not more than three hours and it was already getting fly's going in. Checked it the next day had about an inch of dead fly's in the water. This traps really works great I will order more.