Originally posted by: theridion
Ok, well, a couple things that people should know.
#1 - a 150mW green laser (untested) might only have like 30mW of green, the rest IR. I.e. most lasers on ebay and from not-good companies.
#2 - Don't wear the wrong glasses (or even sunglasses) as it can be WORSE for your eyes. You need to have glasses that specifically block the wavelength of your laser. I.e. My protective glasses make it so everything but a dim orange dot are visible when I use my 132mW green laser. Why not the wrong glasses? Well, when you put on dark glasses, your eyes dilate. If you're wearing sunglasses (for instance) you are blocking just a small portion of the laser light, but your pupils are now big and open.
#3 - There is a pretty good website:
http://www.laserpointerforums.com/forums/YaBB.pl where you can find all the information you want on lasers. I ordered mine from Novalasers (a Canadian company, which also has goggles, prisms, mirrors, diffraction gratings, etc.
#4 - Yes, they are stupid to point at people! That's why high powered lasers are illegal for sale in the US. Novalasers (for instance) is located in Canada (i believe). Customs always has the right to take any (if they find them). I think most out-of-country companies label lasers as 'pens' in order to bypass customs.
#5 - Don't use these in the city. Take them with you camping or out to the desert before you start flashing lights in random directions.
#6 - I believe you have to 4x the power of a laser before it is 2x as visible. Stick with a low powered green laser 5-10 mW. It can still damage the eye, but its much less intense. The beam is still visible in dark locations.