KOO Spectro

VLT
VLT, or Visible Light Transmission, refers to the light that passes through the glass to reach your eye. For example, a dark lens has a low VLT percentage, while a light lens has a higher VLT percentage.

FILTER CATEGORIES
Category 0
Light transmission 80-100% • Colorless or very light filter. Typically sports or protective glasses designed to shield against wind, dust, or dirt, but not against the sun.

Category 1
Light transmission 43 - 80% • Very lightly tinted lenses, usually yellow or orange, suitable for weaker sunlight or protection from wind or dust.

Category 2
Light transmission 18 - 43% • Medium-dark filter suitable for moderate sunlight and casual wear. Their tint is slightly lighter than usual. Can be used for spring and autumn walks on sunny days. They are also useful when driving, especially when frequently transitioning between shade and sunlight.

Category 3
Light transmission 8 - 18% • Dark filter suitable for intense sunlight at the beach or in the city. This category is typical for most types of sunglasses. They are perfect for summer as they provide higher protection against sunlight than the previous category.

Category 4
Light transmission 3 - 8% • Very dark filter for very intense sunlight. Sunglasses for the mountains or the desert, and anywhere the sun is not only extremely strong but also highly reflective. These sunglasses should not be used for driving.