I am doing some research on converting my 3d printer to a laser engraver. The conversion seems simple enough but I am between two types of lasers. I do not know much about lasers other than the higher the MW the more powerful the laser. I am currently looking at these two laser modules

http://www.gearbest.com/3d-printer-parts/pp_368053.html

http://www.gearbest.com/3d-printer-parts/pp_501984.html

One is a 5v 1600mw laser and the other is a 12v 500mw. Does the difference in voltage change anything? even though the 1600mw is the higher power laser, does the lower voltage change anything?

Thanks.