The next higher class, IIIb ranges from 5 to 500 mW. You can also legally purchase this class of laser in the United States. But there are restrictions on it's use, because these lasers are capable of permanently damaging vision. You can't use it in an environment where the beam could escape to the outside. To be explicit here, this means you can't legally use them outside. Now you may want to adopt a "no blood, no foul" attitude, and that's fine for you. But just know that if you ever make a mistake, or run into a narrow-minded individual, you don't have a legal leg to stand on - prepare for a good screwing. Furthermore, based on my own <5mW product, there is no reason outside of inferiority complex to get a higher power product for astronomical use.
So how safe are these things (the sub-5mW class IIIa version)? They won't burn you. They won't cause permanent eye damage. Tests were performed on individuals who were scheduled to have an eye removed for medical reasons. For the purposes of the test, the eye was normally functioning. Test subjects stared directly at 5 mW lasers with there to-be-removed eye for five to fifteen minutes from various angles. No permanent eye damage occured. Some changes in tissue were noticed. Of course, in a real-world incident, laser light entering the eye would likely last for less than one second, as people naturally look away from bright things and close their eyes, so there is no real danger of direct damage.
Having said that, these things are damn bright. If you hit a car driver at night with this, he'd be effectively blinded for at least a few seconds afterwards -- long enough to crash and die and have you go to prison for manslaughter. These are not toys for children. They should never be shined at people ever, and most especially not cars or planes.
Finally, why green? Our eyes are most sensitive to green light. The same measured power output of a red laser would not produce a visible beam, because our eyes aren't as sensitive to red. By the time we could see a red laser, it would probably be reaching a dangerous level of intensity.
It also came in a very nice wooden box, and a pair of batteries. For my order, they were also giving away a free red laser pointer with it. I don't much care about this, but the free red laser pointer was packed into a second plastic foam case, which was much too big for the red laser pointer, but perfect for the green one. I don't know if they always give out this second case for the green pointer, but if you buy a pointer from them I suggest you ask them about it. The wooden box is very nice, but not very practical. The plastic foam case on the other hand is much more practical for slipping into your pocket or some luggage, and it provides nice protection. It closes with a flap that has two snaps in it, and it has slots for a spare pair of batteries. This is the case I'll be using whenever I'm carrying this pointer.
So, how does my laser work? It works GREAT! Exactly as described - a green beam of light protrudes up and more or less stops right on the object you are pointing to. The end of the beam is a bit more blurry, and fades slightly, but it really seems to have an end where the beam essentially stops. It's extremly apparent what you are pointing to. I haven't yet tested to see how far away from me it remains visible, although people standing six feet away from me have been able to see it without a problem. What about light pollution? Many web sites say that in light-polluted conditions you won't see the beam, and you'll need more power. I suppose it depends on what they mean. The first time I used it, I was in a rural area, although not very far from the city, and there was a setting gibbous moon. Limiting magnitude was around 5.0, maybe 5.5. The laser was bright and easy to see.
I've also used it in Cambridge Massachusetts, easily one of the most light-polluted cities on this planet. On the best moonless nights, limiting magnitude is 4.0. Again, the laser is easily visible, not quite bright, but not dim either. However, this only accounts for the light pollution - I was on a dark rooftop on a slight hill above other lights. So the light pollution was in place, but I had no lights in my eyes. If, by light pollution, you mean standing on a brightly lit street with a street light above you, then no, you won't see the beam. But if you mean, can you see it from a dark spot in the worst light-polluted sky imaginable? Yes, you can see it.
Just for perspective, I used it about 45 minutes after sunset. The sky was still quite bright, with 20 minutes of nautical twilight left, and an hour of astronomical twilight. Limiting magnitude was perhaps 3.5. The beam was visible in these conditions. Dim, but unmistakably visible.
These lasers are also supposed to work poorly in cold weather. I've used it in below-freezing temperatures. I was carefully to keep it in an inside pocket, or up my sleeve, when I wasn't using it. It worked fine. It tends to come on at less than full brightness, and then brighten up after a fraction of a second.
The first 10,000 feet gives us a laser beam across almost 90 degrees of our view. And the next 15,000 feet of beam visually lengthens the visible beam by a size smaller than the disk of Saturn, Jupiter, or Venus. In other words, while the beam is fading out gradually, the part of it that we can actually see, the close part goes almost all the way to where we're pointing, while the long long section that fades out, adds almost no visible length to the beam. Even the section of the beam starting after one thousand feet away only lengthens the visible beam by the size of a crater on the moon that's too small to see with the naked eye.
I apologize for writing in this space that Howie Glatter never answered my email. Apparently, spamassassin ate the email, and I found it later. By that time I'd already purchased my product. He has a good reputation, seems a bit pricy, but otherwise I can't comment on the quality of his products or services.
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