lenses
cut for 40 degrees.
Category 3, polarised, brown base. Here is what each of those means.
category 3
The darkness rating. Category 3 passes 8 to 18 per cent of light. It is the darkest you can legally drive in.
polarised
A filter layer that blocks light bouncing off flat surfaces. Water, road, the bonnet. Glare goes, detail stays.
brown base
A slight brown tint raises contrast without shifting colour. Grey lenses dull everything, green lenses turn traffic lights odd.
UV
100 per cent UVA and UVB blocked, on every lens, every colour. Tested to AS/NZS 1067.
scratch coat
Hard coat on both faces. They will still scratch if you put them lens-down on concrete.
the lens is the point.
Every frame gets the same lens. Pick the shape you like.