“class 4” is just the highest class, being over 500mw. Technically, the experimental lasers they use on warships are class 4 lasers.

Most countries don’t restrict owning them, but they do restrict selling them. When you have one, it’s kinda like owning a kitchen knife, perfectly legal, but as soon as you do dumb shit with it, thats still on you.

And class 4 lasers make it VERY easy to do dumb shit.