Hey all,
I stumbled upon this Rudy Project and Challenge Family Sunnies. These sunnies are photochromatic, i.e they change colour with exposure to UV. The light transmission is between 9-74%.
Also, due to this partnership, they are giving out free Spinhawk Sunnies which are worth a minimum of $87 for free with every purchase from the link above.
P.S. you dont have to do step 3. Just select step 1 and step 2 and add to cart.