The world through a TAC G-15 lens. (triacetate cellulose)
Not so dark that cloudy days are out.
Not so light that bright sun days are out.
Crisper vision than polycarbonate.
TAC lenses are polarized. They are multi-layered plastic lenses that start with a polarizing film, then layers of chemical resistance, then layers of UV blockers and finally layers of impact/scratch resistance. All about 1mm thick. Not as shatter resistant as polycarbonate yet clarity is better.
A good all purpose lens.