There are 7 laser classifications (New System, IEC 60825-1) based on the highest power or energy density of a light source from being considered safe to the probability for creating damage this also known as maximum permissible exposure (MPE).
Class 1 is safe under all conditions of normal use, even when viewing a laser with the naked eye.
Class 1M is safe for all conditions of use except when passed through magnifying optics such as microscopes and telescopes.
Class 2 is safe because the blink reflex will limit the exposure to no more than 0.25 seconds. 1mW lasers fall into this category.
Class 2M is safe because of the blink reflex if not viewed through optical instruments. This applies to laser beams with a large diameter or large divergence.
Class 3R is considered safe if handled carefully. The MPE can be exceeded, but with a low risk of injury. Our 5mW laser belongs to this category.
Class 3B is hazardous if the eye is exposed directly, but diffused reflections such as those from paper or other matte surfaces are not harmful. Most of our lasers that are <500mW fall into this category.
Class 4 is the highest and most dangerous class of laser because it can burn the skin, or cause devastating and permanent eye damage as a result of direct, diffused or indirect beam viewing.