There are a lot of rich, fat & happy people because of this well orchestrated gimmick. It's a waste of money. I've never used it and had lots of deer downwind, upwind, and no wind within less than 20 yards. I think it has a lot to do within what circumstance a deer first encounters the "human" scent as it approaches you in the field. Has it been spooked in that area before by humans which would cause it to be leery, are you grunting, rattling, bleating, or anything else which could turn that deers nose on to "super-vac" that begins sucking in every bit of oxygen so as to purposely taste, smell, and scan every single molecule it can to determine just who or what is making that sound. It seems to me that if deer are calm and relaxed and in a "chilled" mode, they can be downwind and not spook. On the other hand, I guess I've even rattled bucks in that were so pumped about fighting that they busted in from downwind and came to within range. It's all circumstantial. I can't think of too many times where I was busted, that it wasn't from the deer seeing me first and smelling me second that caused the bust. Regardless, this is an argument that can't ever possibly be solved because deer can't talk...except silentassassin...who is part monster hawg buck and I believe him and approve of his message.