A dot from a 125mW greenie may be harmful! When I shine my DX 200mw (which is actually putting out around 90-120mw) on a wall that is in the same or adjacent room, it is painfully bright! But I found an incredibly cheap pair of protective red lens goggles at www .ScopeStuff. com -- now I can burn things and do experiments, you won't fully enjoy your high-power laser w/o some goggles !