Spy Dirty Mo was designed for Dale Earnhardt Jr with his imput and comfort in mind. From the 8 mm stop hinges which provide smooth unfolding and folding of the temples. To the 8 x 4 base toric ARC lenses and custom metal details on the temples. The Spy Dirty Mo sunglasses are custom built from high quality Proportionate which is lightweight and comfortable for all day wear. The amount of wrap the Dirty Mo has makes sure to give your eyes full coverage.