This table shows the meaning of the different Classes of Lasers and LEDs according to the current version of EN 60825-1 and IEC 60825-1. A more detailed description is available by going to An Overview of the Laser Classification System.

Class 1 Safe.
Class 1M Safe provided optical instruments are not used.
Class 2 Visible lasers. Safe for accidental exposure (< 0.25 s).
Class 2M Visible lasers. Safe for accidental exposure (< 0.25 s) providing optical instruments* are not used.
Class 3R Not safe. Low risk.
Class 3B Hazardous. Viewing of diffuse reflection** is safe.
Class 4 Hazardous. Viewing of diffuse reflection is also hazardous. Fire risk.

*Optical instruments – binoculars, telescopes, microscopes, magnifying glasses (but not prescription glasses).

**Diffuse reflection – the reflection of radiation from a matt surface such as a wall.