Take a look at the ingredients.
I checked with the vendor (Dover Saddlery) on range/distance of coverage and based on feedback from other users, we have only one hung in the donkey shed.
It has a citrus odor, which I thought might be a bit overwhelming, but after being hung, I detect only a faint smell in the shed. Certainly nothing offensive.
We're not in the thick of fly season yet, so the true test can't be determined at this point.
One down side: The online description and box packaging mentions refills are available, but I couldn't find them on the website. When I called to inquire and they did a little checking, it turns out the price of the refill at about $20 greatly exceeds the cost of the product ($13.99). Doesn't make a bit of sense.
I'll let you know the results.