The new laser classes are described on this page.
Read about the old laser classes>>
 

Class 1

Class 1M

Class 2

Class 2M

Class 3R

Class 3B

Class 4

Class 1
Class 1 comprises lasers with no known biological hazard. Class 1 laser products are either very weak, or are interlocked laser system.

Class 1M (magnifier)
Class 1M comprises lasers with higher output power than Class 1, but with a diffuse beam. This means that the beam can be magnified with help of optics.

These lasers have no known damage.

Visible radiation (wavelength between 400-700nm):
Comprises laser with output power between 1mW and 5mW.
Invisible radiation:
Comprises lasers with higher output power than Class 1, but lower than 5 x Class 1.

Do not watch into the laser beam or on reflections!

Class 2
Class 2 comprises lasers with power up to 1mW. These lasers are not considered an optically dangerous device, as the eye reflex will prevent any ocular damage.

Class 2 comprises lasers with visible light (wavelength between 400-700nm).

These lasers have no known damage, but avoid staring into the beam!

Do not watch into the laser beam or on any reflections! Lasers with high output power might also cause damage to skin!

Class 2M (magnifier)
Class 2M comprises lasers with higher output power than Class 2, but with a diffuse beam. This means that the beam can be magnified with help of optics.

Class 2 comprises lasers with visible light (wavelength between 400-700nm).

Avoid staring into the beam!

Read more at the website of the Swedish Institute for Radiation Protection: http://www.ssi.se