Love this optic for competition shooting. I purchased 3 of them and they work greatC-More Railway is a World Champion Sight used on more Open Class Race Pistols than any other red dot reflex style sight...and for good reasons.Also an effective rifle sightThe housing may be longer than most red dots but that gives the laser beam a significantly longer distance to travel between the diode module and the splitter lens which results in more accuracy for the shooter.Most other red dots also have only one "cross bolt" for mounting which may result in side to side wobble and resulting inaccuracy...Not only does the C-More Railway have 2 mounting "cross bolts" but the rear cross bolt slides fore and aft to allow more mounting options. Also of HUGE BENEFIT...the C-More Railway works on most Picatinny (MIL-Std 1913) AND Weaver Rails. This sliding rear mount facilitates use on " factory" rails which may have intermittent cross slots like Rugar 10/22 rifles or Browning Buckmark pistols. It is possible to purchase and install a third cross mount for really large caliber applications.Keep in mind that position 1 and 2 on the click switch (for intensity) model are for night vision optics and you will not see a red dot in either of these positions unless you are using night vision...there is nothing wrong with your unit.Do not dismay about buying the Polymer body...most semi-auto pistols are Polymer bodied and this is just as "beefy" in the hands as they are...there is a sense of high build quality when you hold/operate the Railway.The Polymer model comes with an extra set of battery cover screws and 3 wrenches...the aluminum body comes with extra screws and 2 wrenches.Uses a 3 volt lithium battery-Duracell DL1/3N or Energizer 2L76Diode modules are available in six different sizes-2/4/6/8/12/16 MOA if you need more than one red dot size at extra cost of courseThe 8 MOA is a good starter size for pistol useSee this link for a factory chart which will assist you in choosing the MOA Dot size you want..http://www.cmore.com/diode.htmlThis unit will co-witness with some higher fixed factory sights.C-More makes the same unit for direct mounting applications and co-witnessing on low mounted fixed factory sights.If you want to direct mount-the Railway IS NOT the model you want...look up the model...Slide Ride. It is basically the same optic minus the mounting railway and because it sits lower via direct mounting to the weapon without a rail...it will co-witness with lower mounted fixed factory sights. To be clear...to direct mount, your weapon will need to be or already is drilled and tapped for optic/accessory mounting.While this unit seems huge, in hand it's smaller than you thought it was going to be...When you are ready to buy you need to decide the following in this order:Railway or Sled RideAluminum or PolymerIf Polymer...what color...aluminum comes in black only (darn...aluminum can be anodized in colors C-More!!!)MOA Dot SizeA bit of a labor intensive shopping experience that results in a really high quality reflex red dot optic purchase....I liken it to picking car options...remember when you could do that...LOLI liked it but the red dot keeps drifting. I have a set of Magpul popup sights that I have for backup. The dot keeps moving right when co-witnessing with the popup sights. It's out of warranty. I'm trying to reach them for repair but the outgoing message says they're closed.UPDATE: I called back on Monday as I missed that they were closed on Fridays. I spoke to someone who took my request seriously and asked me to send it back in for assessment and repair. I'm very appreciative of the customer service and expect the optic to perform wonderfully as the reviews indicate.First impression. Will be using for Steel Challenge. Can already see this will be a big help in getting onto to target faster.This is a fantastic piece of equipment that I nearly rate a 5-star product. I've wanted one of these for some time but I just didn't pull the trigger (pun) until recently. When sighted in there is very little skill or guesswork required to maintain a consistent bead on the target. I do have a question about its durability. The exposed glass and laser projector can easily be obscured by matter from the environment (mud) and I worry that something may get jammed into the laser projector housing. Time will tell just how well this thing stands up.Pros:- When purchased it was on sale for a song so look for those song-like sales- Very accurate when sighted in. I have the 12 MOA setup and it is surprising not too big or not too small...it is just right for what I wanted it for.- Seems study despite the use of high-impact plastics (I do hope they are high impact because I'd hate for it to break after an accidental drop)- Numerous intensities that are quick to switch to.Cons:- When not on sale it can be only a c-note less than an EoTech (which I much prefer)- Does not use a AA/AAA battery system- The "OD Olive Drab" color is more close to a forest green. Yeah...there is a difference and it stands out some on my primarily OD build.- Some of the inject molded plastic left behind little plastic burs that appear to have been filed down by the manufacturer (with a nail file?)Let's start with the reticle. It's very sharp and crisp. I went with the all aluminum model (ATRW). It's light weight with very clean clear glass. My only purpose for this optic is close to mid range defense. I don't do competition shooting so I will review it from a tactical standpoint.Pro infrared night vision capabilitiesPro you can keep both eyes open while shooting, enhancing shooter awareness and fast target aqusitionPro it's waterproofPro adjustment nob makes for quick adjustmentsPro it holds its zero very well making it a breeze to transition between similar weapon platform (my best example is switching from a ar15/m4 to a scar 16 or bushmaster acr basically any platform with the same height site base, or else you would obviously have to rezero).Cons if you plan to get down and dirty with this optic dirt can obscure the diode and you won't be able to see the red dot.Cons day time shooting strains the battery more because the open design causes the user to adjust the brightness to a high setting. If you are looking for a closed design then look into an Eotch or an aimpoint. That's one of the main reasons they have remained at the top for so long.(2 Year update) I've owned an aim point T2 and the only thing I would change on the CMORE is that the windage and elevation nobs need to click per moa adjustments because a flat head will mar the standard nobs and make them every hard to zero. Other than that the CMORE is by far the best red dot on the market, and in my opinion even better than the aim point T2. I'm now a life time customer of cmore.私は今まで実物のチューブタイプのドットサイトを利用していたんですが、取り付けると重くなり取り回しが悪くなっていたので買いました。こちらのドットサイトは実物の中で何より良いのは軽さです。ドットも明るさを段階的に調節でき、明るい晴れた日の外でもドットがとても見やすかったです。ドットの調整には上下左右の移動には、右面の２箇所のロック（一つが皿ネジタイプの六角でもう一つがイモネジタイプの六角）を外してロックを解除してから上下が上面のマイナスネジ、左右が右面のマイナスネジを回せば調節可能です。