We have a class III (<500 milli Watt) 532±10nm (lime green) astronomical laser. It takes a non-standard (but rechargeable) 3.7v Li ion battery.

It is very bright. Although it isn't bright enough to set anything on fire (you can't even feel the beam when it hits your hand) it is bright enough to cause serious vision loss–possibly only short term, but we don't know that for sure – so we treat it with high caution.

Laser Rules

1. Only point the laser at specific inanimate targets; do not wave it around, swing the beam, or point it near any person or animal or place where there might be a person or animal (including houses, cars, airplanes, etc.)
2. Don't hold the button down any longer than needed
3. No horseplay or fighting over the laser
4. Take the tail cap off and the battery out when it's not in use. Remember The "safety" key doesn't always stop the laser from coming on! So don't use it at all, just remove the battery instead.