Works as intended.Thank you.Shockingly well for the priceI wanted to put a reflex sight on my S&W 9mm but I didn't want to have a lot of money into it so I got this one. It is very light and the illuminated reticle is very nice. You can change it from red to green and I love that I don't have to turn it off when I out it away. I just leave it on and after about 10 minutes of not sensing movement, it turns itself off. Then when I pick it back up, it wakes up and displays the illuminated reticle again. How cool is that!? But it is really clear and made well. It fit right on my slide and has kept zeroed in even after 2 boxes of bullets. It may not cost a lot but it was made with excellent quality and materials. This is perfect for me. It should serve me well for a long time. Great product and even better price!I have this rail mounted as i do not know what plate if any this mounts to or maybe it takes the place of the rear sight and drives into the dovetail/slot. Directions are poor but the dot is bright and fine for accurate plinking. Installed on a 9mm sub 2000. Holding zero.This sight is a bit of a mixed bag.I purchased this intending to use it on a G19 clone. Unfortunately, the mounting plate it comes with is NOT compatible with slide-in type sights. For a rifle or something with a Picatinny rail or a pistol with an RMR cut out, it should work. It would also likely work on a Glock if you get a slide in to Picatinny adapter, but you would need to purchase that separately.First the good...It comes with a very nice, padded, hard plastic carrying case. It includes a very nice adjustment tool, two CR2032 batteries (which is nice), 3 Allen style wrenches for mounting, a nicer than average elevation/windage adjustment tool, a dust cover, the RMR plate, and some extra screws for mounting it. The size of the sight is also very small and low profile and should be perfect for pistol mounting. The red dot itself in the eyepiece is bright enough, adjustable, and does not blur out into a starburst at higher settings. It also has an auto-off feature that shuts it down after 5 minutes to conserve battery, which seems to work well. When it has shut off automatically, essentially any movement will turn it back on, making it perfect for pistol use.Now for the bad...The lens itself, while clear, has a coating (anti-fog, etc), but it is not uniform and leaves stuff toward the top with a decidedly bluish cast.It is a very good thing that this has the auto-off feature to save battery life, because changing it is a real pain. You have to remove the two screws that hold the sight to the mounting plate and then flip it over (which means you need an Allen wrench with you just to change the battery). The battery holder itself is of the side-pressure only style rather than the type that has clips all around . This means that the battery wants to pop out on its own and will fall out if you turn the sight over. If you already have your sight mounted and aligned, this means you are going to have to hold the gun upside down in the air above you while you hold the sight on with your thumb to keep the battery from flipping out, and then try to put the screws back in with the other hand. This is hard enough to do in the best of circumstances and something you don't ever want to have to attempt to do in the field.Additionally, the rubber dust cover that comes with it is so loosely fitting that if you turn the sight upside down, it falls off. This makes it almost totally useless when the sight is actually mounted.One other flaw is that the on/off and brightness button is of the simple press to turn on variety, NOT the press and hold style. This means that even getting bumped will turn it on accidentally, making it problematic for use holstered on a pistol.Another very minor thought would be that, while the included elevation tool is much nicer than average, it would be very helpful if they had at least put a hole through it so that it could be put on a keychain or similar.Finally, my biggest complaint is that the description on the purchase page specifically states that this is perfect for a Glock 19, 17, 43, etc yet fails to mention that the mounting plate that it comes with will not fit a typical Glock or compatible unless you purchase another adapter or an RMR compatible slide.The size is good for a pistol, but many of it's issues make it more suited for a rifle, which it is not really sized for. Essentially, the construction is good, but the design itself, not so much.OK. Let's get one thing straight. It's not going to win any awards, except maybe for value for money. It's going to be hard to find something else out there that can give you decent quality at this price. Full disclosure. I still haven't shot this at the range yet so not 100% positive it'll stay true once a few rounds have gone down range. Hopefully it will, in which case I will immediately increase another star. the red dot is bright and at full brightness you can use it outdoors in any bright and sunny condition. The auto power on and power off is pretty cool to have in such an inexpensive lens too.All in all not too shabby. Will have to see how it will perform over time. Will update as needed.This review is for the Gaialoop Red Dot Sight Reflex Rifle Optic Sight. First, I’m not an expert, rather I’ve had some experience with a few military grade sights and right off the bat, this sight is only for airsoft use at best. The sight comes well-packaged and equipped with everything included. Operation is very easy, however I did find installing the battery a bit cumbersome mainly because you need to attached the complete sight on the gun rails first, then remove the body from the rail grip to install the battery. I wish the rail grip had an indication for FRONT so that you don’t end up installing it backwards! The body is aluminum and the unit seems to be well-built and light weight, but I’m not sure if it is robust enough to take the knocks and abuse of heavy use and inclement weather. The red dot is crisp and brightness adjustment is easy, however when you install the battery for the first time it’s set to the most dim setting, which is hard to see leaving you wondering is the unit is working or on. I had to re-seat the housing to the base a few times and fiddle with the unit to finally see the dot. Alignment of the dot is also relatively easy with the supplied tool. Overall, I’d give it 3.5 stars if I could.I placed this on a .22 rifle that I have and may put one on my Gamo air rifle to test it as well. I had to use a dovetail transition to picatinny in order to mount it to the .22 and it actually looks pretty slick. Now for the operations. The optic came with a plastic thumb tool to adjust the elevation and windage. I found that the windage was pretty easily set, but the elevation was easily set but it felt too easy. I don't think it will lose zero on my .22, but I wouldn't trust that on a 12 gauge since the change dials seemed like they might run with the shock of the shotgun. The red dot even at the lowest setting still has a very slight star effect and that gets even more pronounced the brighter you set the dot. Not that big of an issue for me since the .22 is used for vermin around the property. Decent optic for the price. Spend more if the star effect bothers you and you need something to hold zero on a larger rifle or gun in my opinion.