Amy Winehouse

Green laser question – 5MW or 20MW?

Alright – I’m going to order a green laser from Amazon. I don’t want it to be powerful enough to cause eye damage of ANY kind (casual use laser), but I want the beam to be easily seen at night for at least 50 yards or so. I am looking at some green 5MW 532nm (what is nm?) and some 20 MW lasers. I don’t want it to burn or anything, so what so I choose?

<— LASER NOOB