The most impressive thing is that you can still see after playing with a 3W laser with no eye protection most of the time.,(reply>), @Jim Stanley The class 4 lasers I use go through walls. We don't stand in front of them ever.,(reply>), @Trelligan "a bit" is a huge understatement. That "matrix dodge" is never okay, and letting him stick his hand in the beam without everyone involved being goggled up is also incredibly irresponsible.,(reply>), @energy use your brain to find out,(reply>), @energy Because lasers are cheap to mass produce.<br>Cheap doesn't mean its safe. In fact, cheaper usually means more dangerous.,(reply>), @Battlesheep  explain why you can  buy a class 4 laser for less than 10 dollars on ebay