OakleyOakley Men's Oo9463 Sutro Lite Rectangular Sunglasses

Are these genuine Oakley glasses or a look-a-like?

Whats the difference between 37 mm and 39 mm lense size? Head size or just len?

Are the lenses dark? Or see through like it's shown in the picture

Why the option of lens width are 139mm and 39mm? That doesn’t make sense, too much different?