520nm Green Dot Laser Diode Module adjustable focus 5mw Laser

It is perfect for my purposes. I wanted a night sky laser, and it shines very clearly at night, producing a straight, solid beam. I've used it for several nights with 2 AA batteries with no problem. It is easy to tune to a perfect focus, especially with needle-nose pliers. The lens is spring loaded so it doesn't move after being set, even with the jostling that I've put mine through. However, there is a small amount of light that does not get focused into the beam and shoots off to the sides. I've attached two pictures so you can see the performance. The glare photo is from only half a foot away, so it's not too bad. It's everything I need it to be, despite not being perfect, and it is reasonably priced.

I tried this green laser module at 3 volts, and it appears to draw about 200-300ma (I say "appears", because I don't trust the meter in my PSU), and it gets quite warm after a few minutes of usage. The case is metal, and that helps to dissipate the heat. The focus ring has a spring under it, as the pictures in the listing show, and it is actually quite stuff, so you don't need to worry about it being bumped, and changing the focus, because one you set it, it's not going to move. There is a small hole on the side of the case, and I wonder if this for the charge LED, for internal batteries, in a different configuration. The only bad thing I can say, is this comes with no documentation. The listing says 3 or 3.7 volts, but glancing at the regulator circuit, I suspect it can work with a much wider range of voltages.

I bought three separate 3.7v green laser modules from this seller. The other two worked fine but this one is defective. I hooked it up to a 4.2v freshly charged 18650 battery and from two feet away the dot is almost invisible even after adjusting the focus.

laser functioned well, but came with UNSOLDERED pins.... also the regulator pcb was completely different to previous customer review pics and didn't have a dimmer

Fell apart