I have been using one for a while. From what I have seen in the field, definitley not a gimmick but definitley not a cure all either. I had good luck while using in a blind but in a tree, I could tell the deer winded me but the big difference I saw was that they didnt start blowning and running away to the other side of the county. When they would hit my scent cone, they would stop (sometimes), and stick their nose in the air. You could tell they could smell something they didnt like and would turn and walk or slow trot away. These were all small bucks and does so I don’t know if there would have been a different reaction with one of those big boys. Just my experience, I know I will keep using mine!