I agree with most reviewers that this product is a great design and a well made piece of equipment. But reviewers fail to address the bigger question as to why one might bother to use a mirror at all. The reason most bikers go without a mirror is lack a clear understanding the margin of safety and peace of mind they offer. Why is the Safe Zone mirror design best to achieve these objectives? 1. Presence: it is 5 inches from the eye so it is very easy to check with an instantaneous glance. 2. Adjustability: once trained up, you can micro-adjust with one hand with extreme precision in a split second. 3. Stress: most don't realize that unobservable threat of approaching traffic creates psychic stress and fatigue; being able to glance at the threat allows you to position your bike for the type of threat, being car, big truck, or towing trailer. The mirror is a big stress reliever. 4. More access to the road: although most of the time the biker will use road aprons or bike paths, but with the Safe Zone, moving into the adjacent vehicle lane will be appealing. If the mirror confirms that you have no traffic behind you, move over and enjoy better road surface and greater safety of the road itself (not a tactic I recommend for every biker however). Move back on the apron with a judicious time margin when you see approaching traffic. 5. Speed: If you are able to use the road rather than the apron of the road, you will go faster overall. Concentrating on a few feet of margin slows you down.

The product itself: Absolutely superb design and manufacture. I have used handlebar and glasses mounted mirrors and they were useless. Mounting: Straightforward, but I have some suggestions: The mirror comes in three parts, the mirror, the boom, and a foot. The directions show the boom mounted on a diagonal relative to the base of helmet. Better, mount the foot in the most horizontal position relative to the base of helmet and you will have greater ability to adjust to optimal setting and the boom will tend to be more straight without less curve of the boom in the field of vision. The velcro straps supplied with the product are only useful as a trial measure -- use zip ties. When using a zip tie, take a diagonal wire cutter and twist/roll the cut end of the tie tightly against the latch lock. Leave the tag on the outside of the helmet to allow easy re-tightening. In sum, it is commonly said that if you are going long distances, use a mirror. I say, use one all the time and your won't regret it and it might even save your life.

I used one of those helmet mirrors that Velcro onto the under side of your helmet for the last few years. It was a decent product, but I had a few complaints about it. First, the mirror was on the small side, so it required precise adjustment to see what was behind me. Second, the adjustment was loose enough that riding over rough roads would bounce the mirror out of position. And third, the mirror was a bit on the dark side. On bright days, I couldn't see behind me until I was riding in shade. Still, it was useful enough that I didn't bother replacing it until the mirror got so floppy that it wouldn't stay put, even on smooth roads.
The first replacement I tried was a stick-on mirror. But it wouldn't stay stuck onto my helmet. So I decided to try the Safe Zone mirror. I was a little concerned that it might be too large, and impede my side vision of traffic. It does not. The mirror is nice and bright, and large enough to offer a good view behind without being so big that it impedes my side vision. The way it attaches to the helmet is kind of kludgy, but it works well. The Velcro strips on my old helmet mirror were better looking (if such a description is applicable to helmet mirrors), but the functionality of the Safe Zone system is undeniable. The only other thing I find objectionable is the price. It is more than twice the price of the other helmet mirrors, and just doesn't seem to warrant that cost differential. Nonetheless, the product is effective and appears to be durable.

ETA: I have had this product for less than six weeks, and already the mirror fails to stay in place when I am riding on paved (although somewhat bumpy) roads. The mirror is supposed to rotate at its connection to the articulated arm, but only if you choose to rotate it. I am probably going to super glue the mirror in place -- the rest of the arm does not seem to flop around, so I am hoping that fixing the mirror attachment point in the orientation I want will eliminate this irritation. But I expected better from this pricy product. So I am removing one of my initial stars in the product review.

Bicycle helmets look dorky enough and adding a mirror to it only adds to the dorkiness factor BUT I bike 15 miles a day through some pretty congested streets and no longer felt safe driving without one. To all those that are sitting on the fence about buying a mirror, I can't recommend one highly enough. Not having one would be worse than driving a car w/out a rear view mirror in my estimation. This one is PERFECT.

PROS:
-stays on firmly, image on mirror is steady
-arms are very strong, stays anchored well and is easily adjustable (Even on the go)
-easy to place on your helmet (follow the manual instruction). Zip tie anchoring system is low tech but very effective
-most imp't - very easy to see a broad view of objects behind you with NO distortion
-wonderful customer svc - I had to contact the company obtain a few more of the arm thingamabobs (forgot the name but they are what attaches the visor to the helmet) to accommodate my visor. They got back to me right away, sent me the extra attachments at no charge and were just so pleasant to work with.

So yes, I do feel a bit like a Trekkie geek but I LOVE this helmet mirror and will never commute on my bike without one.

The guys I ride with make fun of me because the mirror is larger than any of theirs but I love it. I gives me a wide view of what is behind me and since I am a fashionista and have multiple helmets I have purchased several. Once installed they are difficult to move to another helmet.

It is a ball and socket device and if the mirror comes loose which only happens with a bad knock or me throwing helmet in car ---- I have to have my husband push it back together as I am not strong enough.

I first used a small clip on mirror for my glasses after trying bike mounted mirrors. The glasses frames mirrors are small and the image you see moves too much. So this is my second purchase of an EVT mirror--the first one from over five years ago is on another helmet and has held up just fine, and this one is on a new helmet. I cannot get on my road bike without my mirror--I feel blind and I'd rather be safe and aware of vehicles than worry about looking dorky on the roads.

I have no difficulty doing fine adjustments for line of sight when needed underway. If I do forget to take my helmet off at a rest stop-sure I may bang the mirror against a door (hello Spot-a-Pot) it never does anything but knock the mirror slightly out of alignment. Mine has never come apart or broken in any way, including the reflective surface, nor has it lost tightness at the joints that would allow it to wiggle as you go over bumpy roads. Keep your head steady, look up slightly, and you will have a wide view of what is behind. I have never felt the disc was a "looming object" and I got used to it immediately.

According to an article in the August 24, 2017 Washington Post, bicyclist deaths are up. This mirror is cheap insurance. I am able to see vehicles coming up from behind me and warn riders ahead without mirrors. I was once on a road with no paved shoulder, lots of oncoming traffic, and I saw a large box truck coming from behind. I saw it in time to get off the road--fortunately it was grass so I was OK. I do not like to consider the alternative. I live in a heavy traffic area on the mid-Atlantic coast where not every driver is "bicycle friendly."

Be smart and be aware if you are a road biker--get a good mirror. By the way, I got my first one after talking to another rider at a rest stop, so it was his endorsement that made me buy my first one.