About the color of lens about snowboard goggles, only one basic lens is needed for all weather conditions. But it is common to choose two or more lenses to adapt to different weather and weather conditions. There are two ways to mark the transmittance of lens.
VLT that means Visual Light Transmittance, the transmittance of visible light, expressed as a percentage, CAT that means Category Number, denotes transmittance grading.
CAT and VLT:
CAT-4 = 3% ~ 8% VLT
CAT-3 = 8% ~ 18% VLT
CAT-2 = 18% ~ 43% VLT
CAT-1 = 43% ~ 80% VLT
CAT-0 = 80% ~ 100% VLT
Lenses are recommended to be coated, usually iridium coated, mainly to prevent glare and provide additional light balance.