What does the category 1 2 3 4 on the tag stand for?
Transmittance: the transmittance or penetration of visible light. For example, the transmittance of sunglasses is 40, which means that only 40% of visible light can pass through the lens into the eye.
- Category 1: Light-colored sunglasses –The transmission ratio is 43%-80%, these are not sunglasses; however, they do provide limited sun glare reduction and some UV protection. Fashion spectacles with category 1 lenses are not suitable for driving at night.
- Category 2: Light-colored sun-shading sunglasses – The transmission ratio is 18%-43%. These sunglasses provide a medium level of sun glare reduction and good UV protection.
- Category 3: Sun-shading sunglasses– The transmission ratio is 8%-18%. These sunglasses provide a high level of sun glare reduction and good UV protection. It is suitable for outdoor activities such as seaside, mountaineering, etc.
- Category 4: Special Sunglasses – The transmission ratio is 3%-8%. These are special purpose sunglasses that provide a very high level of sun glare reduction and good UV protection. Lens category 4 sunglasses must not be used when driving at any time. It suits for skiing, desert, welding and other environments.
How to know sunglasses anti-ultraviolet performance is good?
QB2457-1999 and GB10810. 3-2006 are a unified standard for domestic sunglasses production, which can isolate at least 95% of UVA and at least 99% of UVB.