We were introduced by a local exterminator company, of course at a much greater cost. It helped but needed refreshed with new product. Buying the package we did, we have plenty for the next round in a few months. Our fly problem appears to have pretty much been eliminated. We are attributing most of the progress to the success of these pads. There is no odor. All good.
I have tried this on a limited scale and have found as an indoor product it works. After placing two in my home I would notice a fly come in when the door opened, notice it for a little while, then it was gone. I can live with that!