According to the international standard IEC60825-1, safety class of laser is divided from class 1 to class 4 based on parameters such as 

                         laser output power and wavelength. Class 1 is the safest and class 4 is the most dangerous. 

                         Below are specific instructions for each level.

                         A. Class 1 laser: the safest laser, with a relatively low output power and will not cause damage to human eyes. Even direct exposure to 

                         Class 1 lasers will not cause eye damage.

                         B. Class 2 laser: output power is higher than Class 1 laser's, but still does not cause permanent damage to eyes. If you look at a Class 2 

                         laser beam for a long time, it may cause temporary visual disturbance but won't cause permanent damage.

                         C. Class 3 laser: output power is much higher, and it can cause permanent damage to the eyes. Therefore, appropriate safety protections 

                         must be taken to protect eyes from laser damage.

                         D. Class 4 laser: the most dangerous one. Output power is very high and can cause blindness in an instant. In addition, Class 4 lasers may 

                         also cause damage to skin, clothing and other materials. Therefore, very strict safety protections must be taken when using Class 4 lasers to 

                         avoid personal injury.

                         International laser safety standards mainly include below.

                         A. ANSI Z136, a laser safety standard issued by the American National Standards Institute (ANSI). It is similar to IEC60825-1 and also includes 

                         the classification, marking, safety distance, protective measures, etc. The difference is that ANSI Z136 also stipulates the daily maintenance 

                         and safety management of laser equipment, and is a laser safety standard widely adopted in North America.

                         B. CE EN207, one of the laser safety standards issued by the European Union. It mainly stipulates the design, testing and marking of laser 

                         protective glasses. This standard requires that laser protective goggles must undergo strict testing to ensure that they can effectively protect 

                         human eyes from damage caused by laser radiation.