Category S3 / Sunny, clear days.

In simple terms: the Category S3 means that the lens is dark, ideal for sunny and clear days.

Its VLT range is between 8% and 18%, which means it blocks the vast majority of outside light to protect your eyes from sun glare and the reflection off white snow.

It's the typical mirrored or black lens you use when there isn't a single cloud in the sky.