Boston Type 2-Way Sunglasses (Photochromic Lenses) | Zoff | UNITED ARROWS This is a collaboration product between UNITED ARROWS and Zoff. These lightweight sunglasses feature photochromic lenses that change color depending on the amount of UV light. The lenses become transparent indoors or in places without sunlight, so you can use them as both sunglasses and eyeglasses with just one pair. They subtly incorporate a structure that prevents slipping at the nose and ears, making them more functional than they appear. I've used them a few times, but they are in good condition.