Why not a 1mW green laser?
I have tested a few "1mW" red lasers (the button cell ones and the AAA pens) and they are more often than not greater than 5mW. Cheapo red lasers do not have any regulation other than a limiting resistor so the power delivered to the diode - and therefore the optical output power of the laser - is dependent on the battery's charge. One red pointer I tested averaged
13mW.
What say you now about the safety of cheapo red lasers?
If you want something that is eye safe (not that direct exposure is ok) and bright a 1mW greenie from a reputable vendor will be ok. As others pointed out, a fog/smoke machine from the local party store will bring out the beam.
Here you go:
http://www.laserglow.com/GLY - Laserglow - Canada based, good company, reliable products
FDA Safety Class II Green Laser - Legal UK, Australia, European Union - Z-bolt - USA based, good company, reliable products
Z-bolt's laser pointers have an integrated power control circuit and an IR filter. It is more expensive than the generic brand lasers but you can rest assured that this laser is ~1mW.
The same goes for LaserGlow's pointers but their models are <3mW and <5mW.
Personally, I think 5mW is just fine but maybe I'm crazy.
Also, it would be a good idea to tell the boy sternly that never, under any circumstances should he point the laser at eyes or vehicles. "Idiot proofing" only goes so far. The best safety is information and education. As long as you provide a good example of safe and responsible use, you can get your son whatever you want.
Addendum: It may be worth mentioning that on a dark night with a bit of humidity, a 1-5mW green laser's beam will be visible enough to point out stars and whatnot. The dot will be bright enough to see for a modest distance. A red laser of equal power, however, will never be as visible as a green laser in any circumstance.
