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About Sunglasses Lenses

What do categories 1, 2, 3, and 4 on the hang tag represent?

Transmittance (Transmission coefficient): the transmittance or transmissivity of visible light. For example, the transmittance of sunglasses is 40%, which means only 40% of visible light can pass through the lenses and enter the eyes.

Class 1: Light-colored sunglasses; Transmittance 43% -80%, lightest color, least shading and reduced light transmittance, mostly used for fashion accessory mirrors

Class 2: Light-colored sun visors; Transmittance 18% -43%, slightly lighter in color, suitable for cloudy or cloudy days

Class 3: Sunvisors; The transmittance is 8% -18%, and most sunglasses belong to this level, suitable for outdoor activities such as seaside and mountain climbing

Category 4: Special purpose sunglasses; The transmission ratio is 3% -8%, suitable for use in environments such as skiing, deserts, and welding.

According to driving requirements, the transmittance should be greater than 8%, so the fourth type of sunglasses is not suitable for driving. Some sunglasses can make it difficult or impossible to recognize traffic lights, making it highly susceptible to traffic accidents due to poor transmission ratio.

How do I know if sunglasses have good UV protection performance?

QB2457-1999 and GB10810.3-2006 are the unified standards for the production of sunglasses in China, which can isolate at least 95% UVA and at least 99% UVB. As long as sunglasses are sold in China, these two standards will appear on the certificate of conformity.

Sunglasses with UV protection generally have the following markings:

UV400: The average transmittance of ultraviolet light with a wavelength below 400nm through the lens shall not exceed 2%

UV, UV protection: indicates that the average transmittance of ultraviolet light with a wavelength below 380nm through the lens is not more than 2%

100% UV absorption: This indicates that the lens can almost completely filter out ultraviolet rays in all wavelength ranges, with an average transmittance of no more than 0.5%.

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