Laser Class

No, not where you sign up to learn how to emit coherently.

Commercial lasers are categorized into 4 basic classes (with some further subdivisions), on the basis of wavelength and power (directly related concepts in EM radiation).  I'm not going to give the actual power ratings, though, because they can apparently vary depending on the construction and type of the laser.  Most classification is done instead by "accessible emission limits," a formula depending on power, exposure time, and distance from source.

Class 1 lasers are the least dangerous-- there's still no good reason to look into them, but they're unlikely to do any real damage if you do.   Class 1M lasers are safe for all use except under magnification, which tends to increase the power over the safety limit.

Class 2 lasers are more powerful but still basically safe, since the eye under normal conditions will blink to protect itself if you accidentally look into the beam, and this will cut off the exposure.  Deliberately staring into it will cause damage.  Laser pointers are often Class 2 lasers.  Class 2M is the next half-step up-- the same rules apply, except (like 1M) in the case of magnification.

Class 3R lasers are dangerous if you look directly into them, but safe if the beam is at all diffused (by reflection off of a matte surface, for example).  Class 3B is slightly higher again, and lasers of this class require protective eye wear when using, and are equipped with key switches and safety locks.

Class 4 is the most powerful class of lasers-- the beam can not only cause damage to the unprotected eye, even indirectly, but it's also powerful enough to burn skin, or light flammable materials.  Most lasers of this class have industrial, medical, or military applications.

Class 5 lasers don't exists, but if they did, the one from Real Genius would probably qualify.