In a scenario full of variables, this is as close to empirical testing as it gets. Joined several other hunters at a good outfitter for a guided archery hunt. All experienced hunters, we had nearly the same scent control protocol (hunters and camos washed in scent free soap, neither camos or boots worn around camp and lots of spray before walking to the stand). Maybe the only difference was that I put my Sitka's in a scent crusher halo for an hour before each hunt and my "rabbit's foot" of eating a couple of apples to kill my carnivore breath. Set up my zero trace a few feet over my head and into the wind. One other hunter used an ozone emitter (Zero Trace is a plasma ion field generator). Results: We were the only two who were covered up in deer at every sit. I have never been upwind of a HEARD of deer a stone's throw away and not been blown. Dead calm, a smart old doe kept eyeballing my general location (just 7 yards away) but never blew or stomped and went back to grazing. Other hunters complained about not seeing much of anything or getting busted by deer under the stand. Before using Zero Trace, I have never had so many deer so close without getting busted. I am convinced that it works.

The item description said the unit comes with 2 batteries, mine did not!!!!!! Only came with one..

I just got this product a few days ago from Amazon, I had read reviews and was worried about fan noise. Yesterday I unpacked product and started it up, very easy to set up. I wanted to check the noise of the fan, my question is what noise? The deer would have to be in blind to hear it, as it was 2 feet from my left ear. I had it at 50%, so I turn it to 100%, no way a deer could hear it at 20 feet and if it could, it wouldn't have a clue as to what it was. Some of the reviews stated that no deer showed up, which is nonsense, maybe there wasn't any deer around that day. As to scent elimination I will write a review on that also, as our bow season start on Sept 18th. I am sure, if you use scent free products, this product will make sure the deer don't smell you. Plus it neutralizing airborne molecules, dust, pollen and bacteria. this product could be the game changer!
It's now Oct2nd, and I am back to report about scent elimination. I have been out 4 times bow hunting so far and have not been busted. (5-12 deer each sit) The last time a had a doe and 2 fawns, also a 4 pointer in front of me for about 45 minutes. Most of the time they were between 8-20 yards away, they left at dark for a bean field. The wind was from the north at 8 and deer were south of stand, not once were they alert that I was there. This product works great! I am now giving it 5 stars.

Only possible issue I see is it's a little loud on the high setting. I use it in my tree stands and ground blinds in all wind directions and I'm still seeing deer, so its sure not hurting my hunts.

First of all, let me say, if your unit is loud, send it back. I bought two of them last year and used them extensively here in PA and on leases in IL and OH and I can barely hear them right above my head; they make no more noise than a very soft whisper.

I've used this product for two seasons now and I'm quite impressed with it. While I didn't kill a deer last year, I passed on bucks up to 4 1/2 years old and saw many smaller bucks. The best example I can cite was last year on a 10day hunt in Illinois. I had one stand that was upwind of a narrow corridor between a pond and a treeline. The distance from my stand to the trees along the pond was 17 yards, but I decided to try the Zero Trace anyway. In three sits on that stand, I saw 16 bucks - most 2 1/2 to 4 1/2 years old - and a number of does and fawns. All passed through the 17-yard corridor downwind of my stand and none but two young deer showed the slightest bit of awareness of my presence. What is particularly interesting is that the two young deer, one a spike and one a doe fawn, clearly smelled "something" that got their attention. However, they didn't spook. Both passed my stand at about 10-12 yards, stopped directly downwind of me, put their noses in the air and walked directly towards me, sniffing the entire time. Needless to say, I didn't move, the deer sniffed the air for 10-15 seconds, then walked away. What they smelled, I have no idea, but whatever it was, they didn't spook.

I'd like to add that I am very careful about scent control and, despite the apparent effectiveness of the Zero Trace, I continue to do so. I use one to de-scent my clothing and one on stand and I'm completely convinced that they are effective. Again, if you have one that makes as much noise as some previous reviews have claimed, send it back; it shouldn't make that much noise.