sunglass filter category

[Yeap]

Hi, i have a question about some sunglass which having a Filter Category, is anyone can explain here how to categorize it? base on what standard?

thank you..
:cheers:

[Darryl Meister]

In many standards, including ANSI Z80.3 and ISO 8980-3, the "category" of a sunlens is defined by its luminous transmittance. You will need to determine the standard in question first, since the specific requirements and definitions of these categories often vary.